Triple Chocolate Mousse Cake

I think the first time I saw this recipe in Cook’s Illustrated, my jaw dropped – literally.  I had seen several pictures of similar desserts around the interwebs and it sounded amazing, but none of the recipes seemed totally reliable to me.  Well, reliability has never been an issue when it comes to Cook’s Illustrated so I knew right away that I had found “the one”.  I also knew that this is exactly the sort of thing can render my will power useless, so I would have to have an occasion to serve it with lots of people around to enjoy it with me.  Our “yay for one mortgage” party seemed like the perfect opportunity to finally try it.  It was everything I was hoping it would be.

The bottom layer is a sort of flourless chocolate cake, the middle layer is a silky chocolate mousse and the top layer is a light yet rich white chocolate mousse.  Yum, yum, and yum!  My only (very tiny) complaint about this dessert was that after baking and cooling, the bottom layer retracted away from the sides of the pan so much that when the second layer of mousse was spread over the top, it filled in the gaps.  From the outside before cutting, it appeared to be only a double layer cake.  I know this is a trivial issue, but it really bothered me.  Of course, once I took a bite I couldn’t have cared less about that.  Once it is sliced, all three perfect layers show beautifully and topping with chocolate curls completes the look.

In case you have the same penchant as I do for anything triple chocolate, here are a few more favorites:
Chewy, Fudgy Triple Chocolate Brownies
Triple Chocolate Cupcakes
Chewy Triple Chocolate Cookies

Triple Chocolate Mousse Cake
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For the bottom layer:
6 tbsp. unsalted butter, cut into 6 pieces (plus extra for greasing the pan)
7 oz. bittersweet chocolate, finely chopped
¾ tsp. instant espresso powder
1½ tsp. vanilla extract
4 large eggs, separated
Pinch of salt
1/3 cup light brown sugar, packed

For the middle layer:
2 tbsp. cocoa powder, preferably Dutch-processed
5 tbsp. hot water
7 oz. bittersweet chocolate, finely chopped
1½ cups heavy cream
1 tbsp. granulated sugar
Pinch of salt

For the top layer:
¾ tsp. powdered gelatin
1 tbsp. water
6 oz. white chocolate, finely chopped
1½ cups heavy cream

For garnish:
Chocolate curls or cocoa powder

To make the bottom layer, butter the bottom and sides of a 9-inch springform pan.  (I lined the bottom of the pan with a parchment round for easy removal later.)  Center a rack in the oven and preheat to 325˚ F.  Combine the butter, chocolate, and espresso powder in a large heatproof bowl set over simmering water.  Stir occasionally until the mixture is smooth.  Remove from the heat and let cool slightly, about 5 minutes.  Whisk in the vanilla and egg yolks.  Set aside.

In a stand mixer fitted with the whisk attachment, beat the egg whites and salt on medium speed until foamy, about 30 seconds.  Crumble half of the brown sugar into the mixing bowl with your fingers to remove any lumps.  Beat until incorporated, about 15 seconds.  Add the remaining brown sugar and continue to beat on high speed until stiff peaks form, about 1 minute more.  Using a whisk, mix one-third of the beaten egg whites to the chocolate mixture to lighten it.  Fold in the remaining egg whites gently with a rubber spatula until no streaks remain.  Pour the batter into the prepared springform pan and smooth the top with a spatula.

Bake until the cake has risen, is firm around the edges and the center has just set but is still soft (should spring back after pressing gently with a finger), about 14-18 minutes.  Transfer the cake to a wire rack to cool completely, at least 1 hour.  Do not remove the cake from the pan.  (If not making the second layer right away, cover with plastic wrap and refrigerate until ready to proceed.)

To make the second layer, whisk together the cocoa powder and hot water in a small bowl; set aside.  Melt the chocolate in a heatproof bowl set over simmering water, stirring occasionally until smooth.  Once melted, remove from the heat and let cool slightly, 2-5 minutes.

In the clean bowl of a stand mixer fitted with the whisk attachment, whip the cream, sugar and salt on medium speed until the mixture begins to thicken, about 30 seconds.  Increase the speed to high and whip until soft peaks form when the whisk is lifted, 30-60 seconds.  Whisk in the cocoa powder mixture until smooth.  Using a whisk, mix one-third of the whipped cream to the chocolate mixture to lighten it.  Fold in the remaining whipped cream gently with a rubber spatula until no streaks remain.  Pour the mousse into the springform pan over the cooled cake and tap gently on the counter 3 times to remove air bubbles.  Gently smooth the top with a spatula.  Wipe the inside edge of the pan to remove any drips.  Refrigerate for at least 15 minutes while preparing the top layer.

To make the top layer, sprinkle the gelatin over the water in a small bowl and let stand at least 5 minutes to soften.  Place the white chocolate in a medium bowl.  Bring ½ cup of the cream to a boil in a small saucepan.  Remove the pan from the heat, add the gelatin mixture and stir until dissolved.  Pour the hot cream mixture over the white chocolate and let stand about 1 minute.  Whisk until the mixture is smooth.  Cool to room temperature, about 5-8 minutes, stirring occasionally.

In the clean bowl of a stand mixer fitted with the whisk attachment, whip the remaining 1 cup of cream at medium speed until it begins to thicken.  Increase the speed to high and whip until soft peaks form when the whisk is lifted, 30-60 seconds.  Using a whisk, mix one-third of the whipped cream to the white chocolate mixture to lighten it.  Fold in the remaining whipped cream gently with a rubber spatula until no streaks remain.  Spoon the white chocolate mousse into the pan over the middle layer.  Smooth the top with an offset spatula.  Return the cake to the refrigerator and chill until set, at least 2½ hours.  (Note: Do NOT cover your pan with plastic wrap unless you are completely sure you can do so without it touching the top of your cake during placement or removal.  If it does touch the cake, it will smudge the perfectly pristine top, forcing you to make an excessive amount of chocolate curls.  I speak from experience.)

Source: adapted from Cook’s Illustrated, November/December 2009

74 Responses

  1. Wow… this looks amazing!! Must try soon 🙂

    • I made this on Sunday and served it last night for my parents 30th wedding anniversary and it was spectacular. I never thought I could make such a beautiful dessert and it came out perfect. I followed other posts and didn’t grease the sides either. I cut out a parchment circle and it worked great. I must confess I’m a chocoholic too and this left me speechless. Love your site, keep up the great recipes, I check daily!!!

  2. As a serious chocoholic this is absolutely “the one” for my twins’ birthday party next week! Mention the words ‘triple chocolate’ and I’m most likely to make it ASAP. Thanks so much for the recipe, Annie!

  3. BTW, I’ve had wonderful results using recipes from the Godiva chocolate site-Chocolate Raspberry Truffle Mousse Cake and Triple Chocolate (the magic words!) Kahlua Mousse Torte were chocolate nirvana! There are tons of super recipes that I’m sure you’d love so I really recommend checking it out sometime.

  4. wow! it’s about 7am and I am DROOLING over that cake!

  5. WOW!!! I would pay anything to get a slice of that right now! 🙂

  6. YUM! this looks amazing!

  7. This recipe is truly The Bomb. I have made it three times, which is a rarity for me, because I always want to try new recipes, instead of repeating the tried & true. The second time I made it, I had some trouble incorporating the cocoa/water/chocolate mixture into the whipped cream. I think I let it cool too long. That layer was still good, just not as smooth as it should have been. It had the effect of having tiny morsels of chocolate in it. I served it, without apology ( a lesson from Julia) and my guests thought it was delicious just as it was. But I have to say, the smoother version is the way to go. Love your blog…the photos & recipes are wonderful!

    • Joan, I completely agree about serving things without apology. That is one of my favorite things I learned from reading My Life in France. I was tempted to apologize for the appearance of this cake but remembered my rule, and I’m glad I didn’t. Everyone was blown away and I think I’m the only one who noticed the outside. A wonderful lesson!

  8. Yum, Yum, Yum. I love Cooks Illustrated and America’s Test Kitchen, they are so reliable. They make me feel a lot more comfortable trying a new recipe. This looks so good, and beautiful too!! Congratulations on 1 mortgage. Wooo Hooo!!!

  9. When I saw this in Cook’s Illustrated I knew I had to make it as well! Still haven’t, but it’s sure high up on my list 🙂 Yours is SO beautiful! The layers looks so perfect from the angle you captured in the picture. Even if you were trying to hide smudges, I love your addition of chocolate curls – gorgeous! And anytime I hear ‘triple chocolate’ anything, I want some!

  10. Now that is one incredible cake…….I do love chocolate!!

  11. Hi Annie. I’ve made this cake twice and have to say that your chocolate curls are way prettier than mine! I had the exact same experience the first time with the bottom layer shrinking away from the sides. The second time I made it, I didn’t grease the pan at all — just used a parchment round on the bottom. And the problem disappeared completely. Thanks for so many great posts!

  12. I, too, fell in love with this recipe. I actually made THREE of the bottom layer because I was so frustrated that it kept pulling away from the sides. The first time, my chocolate was too dark and it came out really dry (and shrunk (shrank?) away from the sides more than 1/2 inch. The second time, it didn’t shrink as much. The third time, I didn’t grease the sides of the pan. The cake only pulled away a bit at the top (and stayed attached at the bottom). I slid a knife between the side of the pan and the cake before I put the mousse on.

    But I digress. That thing is DELICIOUS. I need to make it again, and soon.

  13. Oh WOW. I think I just found what I want for Mother’s Day.

  14. Yay!! I am so glad you posted this today… I was hoping it would be posted before Mother’s Day. Qusetion.. did you make your cake the day before or the day of? I am wondering is it okay to leave it in the refrigerator overnight uncovered? How long did you leave the cake out before serving it? Also, just to be clear, you remove the cake from the springform pan after it is all done and has set in the refrigetator for at least 2 1/2 hours, correct? Sorry for all the questions….

    • Lindsey,
      I made it the day before. It’s fine to leave it in the fridge uncovered. I didn’t really leave it out before serving. Don’t remove from the springform until the completely assembled cake has chilled for at least 2.5 hrs.

  15. umm…wow. this looks so good. Like you, I will need an occasion to make it so that I don’t have it tempting me in my house! You can bet this is going on my “to-make” list though! beautiful picture too 🙂

  16. Annie, this looks CRAZY GOOD! No surprise there or anything… but wow! You constantly impress us!

  17. I made this cake over the weekend and I agree, I was slightly annoyed that the sides of the cake pulled away from the pan. I wanted that fantastic-looking triple layer cake but mine only looked double-layered until it was cut. However, the taste is out of this world. The guests I served it to said it was hands-down the best chocolate dessert they had ever eaten. Your picture is stunning, by the way! I love the chocolate curls…

  18. Annie – beautiful cake! I bet it’s so creamy and delicious. it’s only 7:37a here but I could totally go for a slice. Maybe some fleur de sel sprinkled on top would give it a yummy salty/sweey combo!

  19. Wow, triple chocolates, soooo good and delicious !

  20. I have the America’s test kitchen cookbook with this on the cover. My jaw dropped at the sight of it, too! The missing layer on the outside would have bugged me too. It looks so so SO good, just like the ATK version. Nicely done!

  21. Thanks for posting this!! I have been waiting for you to post this recipe! I can’t wait to try it!!

  22. This cake looks so delicious and soooo tempting!

  23. Looks divine! Happy Mother’s Day!

  24. Dear. God. That looks amazing. We were in the same two-mortgage situation for about the same amount of time as you guys, and though we have been happily paying one mortgage for the past month, I think we need to celebrate. Again. With this cake.

  25. WOW!!!! That is all I can say. That cake is so pretty and yummy. Thanks for the detailed instructions and tips. Will be making this cake in the near future for my hubby since he loves chocolate.

  26. amazing colours and cake!

  27. This looks delicious! Love Cook’s Illustrated and love triple chocolate anything!

  28. Yum! I have been waiting for this recipe! Thank you for posting it.

  29. I’m so surprised you didn’t make a true mousse for the second layer! The flourless cake sounds perfect, though. I love how the richness of the layers gets lighter as you move up to the white chocolate mousse. I will have to try out the white chocolate mousse and cake layers. I have a true mousse au chocolat that I love that I could use for the second layer. YUM!! Thank you so much for sharing this!

    • Well, I followed the Cook’s Illustrated recipe and since they test every recipe a ridiculous number of times, I knew it would meet my standards. Plus, I knew that their recipe would have the perfect quantity for the middle layer so that all three layers were equal heights. If I had used my regular chocolate mousse recipe, I would have been just guessing and then it probably would have looked uneven.

  30. I made this in Jan for my mom’s birthday. She loved it. It was so good and creamy.

  31. We serve a similar cake to this at the restaurant I work at. It’s by LaRocca, and is called a “Truffle Royale” It looks alot like this, the only difference is that it’s topped with a chocolate ganache, and the sides are covered in chocolate curls. It is the devil (as this one you posted surely is!) Too freakin’ good! I can tell you I will never make this

  32. Hi, I only have an 8-inch springform pan – I do know the recipe calls for 9 inch pan. I’m afraid my 8-inch won’t be able to handle the job well??? What do you think?

    Thanks for posting the recipes – I’m having friends over and totally using the recipes for the dinner. I cannot wait to try!!! Thank you!

    • Haejin,
      The 8-inch pan won’t cut it. You would have to reduce the quantities of each layer for it to fit, but I’m not sure exactly how. If I were you, I would just invest in a 9-inch springform. They aren’t expensive and they are what most recipes call for anyway.

  33. Ooo, this is heavenly, Annie! I made a chocolate mousse just recently, and learning to make a cake with it is my next step.

  34. Hi, Annie,
    I’ve made this cake twice (to a couple big groups to avoid that temptation factor) and agree with you that it’s great. I read the remarks on the CI bulletin board about the problem with the bottom layer pulling away, and learned a lot from them.
    My second attempt was better. I didn’t grease the sides, and it didn’t retract much at all. And this time I used a Parrish Magic Line cheesecake pan (Amazon) instead of a springform. I had watched online Alice Medrich use this pan on a show with Julia Child, and she raved about it, so I got one.
    Thanks so much for your blog! I trust your recipes and tips, and your photos are beautiful 🙂

  35. i love the white chocolate on top! this cake couldn’t get any chocolatier!

  36. And when I saw your picture my jaw dropped too!!!
    Great cake, and great shot!

  37. That is one magnificant cake. Three layers of pure joy!

  38. Do you deliver?? Looks just divine!

  39. It is beautiful and very tempting!

  40. Hello again Annie,
    Most flourless cakes will get my initial attention.
    You brought my appetite for luscious desserts to another level.
    Thanks so much for sharing your talents in the kitchen.
    Flavourful wishes and Happy Mommy’s Day!

  41. Simply amazing!!

  42. WOW this looks amazing. Will definitely have to test it out to satisfy my sweet tooth!

  43. Wow, that looks heavenly! I’ve been thinking about chocolate mousse lately, so this is right up my alley. Wonderful. 🙂


  44. Wow, this looks so rich and decadent!

  45. I made this for mothers day and omg. It was amazing. Definatly a keeper and I love that I can use the layers in different ways. Very rich..very good! Thank you!

  46. Now it’s my jaw’s turn to drop! This looks fabulous!!

  47. I made the cake on Saturday for my Mother’s Day dessert. Thanks for your replies to my questions! It came out very well. My bottom layer did retract from the sides a bit (but still looked like 3 layers from the outside) despite not greasing the sides of the pan (did do the bottom though), but my bottom layer was quite crumbly when cut. Did you or anyone experience this? Also, I wonder how semi sweet chocolate would work for one of the layers?

    • I’m sure you could use semisweet chocolate for a layer, but I think they wrote both layers using bittersweet just so you would only have to buy one type. Sugar is added to the second layer, essentially making it semisweet.

  48. Hi Annie,

    I would really like to make this cake for my coworker’s upcoming birthday party. I can’t eat gelatin for religious dietary purposes and was wondering if I could substitute the top layer with heavy whipped cream mixed in with white chocolate? I am thinking it needs to be a bit more solid. What would you suggest? Thanks!

    • Amber,
      You are right, you could just use a regular white chocolate whipped cream. Cook’s Illustrated included the gelatin because it sets better and looks prettier when sliced, but you could leave it out. It just won’t be as solid.

  49. WOW. This is quite possibly the most delicious thing I have ever eaten. It is sooooo worth making!

  50. I just made this for our Anniversary . Can’t wait to try it. The top layer wasn’t as pristine as it sounds like it should be…I always have trouble with white chocolate. It was a little rippled and chunky – could it have started to separate?

    • Chris, yes, that layer should be perfectly smooth (it was for me). I am guessing the chocolate was not cooled enough before you added it to the cream. Hopefully it still tastes good anyway!

  51. I LOVE this cake! It is so super rich and deeeeelish! I served with a rasberry sauce and fresh rasberries the colors were so pretty together! Thanks for the wonderful cake! I found your site searching for butterfly cupcakes for my daughters Birthday party I CANT WAIT to try them thanks for all your awesome posts!

  52. Thanks for posting this! I made this recipe yesterday for my daughter’s 20th birthday, and it was fabulous! I made no changes, except that my cocoa was not dutch-processed, and I didn’t grease the pan as so many suggested. It was a triumph!

  53. Are the mousse layers in this cake stable enought to use between cake layers as filling?

    • I’m not sure, I’ve never tried them with that in mind. I would think not because they need time to set up before you could add the top cake layer.

  54. Hey Annie!

    Thanks so much for this recipe! I really wanted something I felt comfortable with. I made this for an event and the clients LOVED it! It was a real hit.

    Peace and Cupcakes,

    Jessica @ Jessiker Bakes

  55. Is bittersweet chocolate the same as dark chocolate? I thought yes, but now I’m not so sure!

  56. this is PERFECT! i have a question though, can i turn this recipe into a cupcake? a co-worker is crazy about chocolate mousse but wants it in a cupcake for her birthday. thanks!

    • I can’t see this recipe adapting well to a cupcake. You could just make a chocolate cupcake and fill it with chocolate mousse.

  57. This cake looks soo amazing! I’m gonna try it this weekend.

  58. I made this cake yesterday for my boyfriend’s birthday – delicious! His favourite dessert is chocolate mousse, so it was a winner for sure. I used an 8-inch spring form pan, and just had some extra leftover white chocolate mousse, which I put in the fridge and piped around the top of the cake before serving. To avoid the plastic wrap messing up the top of the cake, I just used a slightly domed pot lid that was larger than my spring form pan – it rested on the edges of the pan without touching the top of the cake.

  59. hi annie,
    i ve drooled over u re blog so many times…but actually never tried to make naything…just waiting to lose all the babyweight i vegained b4 i make anything…..unfortunately,i ve very low will power…..anyhow,i want to make this triple chohcolate fo rthis thanksgiving… the expense of sounding extremely stupid,i want to ask u a few questions….can u tell me which bittersweet chocolate u used….i only c semisweet chocolate at the baking aisle …also which instant espresso ….i m sorry,i just want to get it right….thanks so much

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