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This amazing Chocolate Mousse Cake recipe combines moist chocolate cake layers with a rich chocolate mousse filling and a warm chocolate frosting poured on top. It’s the ultimate chocolate lover’s cake!
Chocolate Mousse Cake is the most magical chocolate cake!
Chocolate Mousse Cake is the most magical chocolate cake!I love this Chocolate Mousse Cake because it’s the perfect balance of elegance and ease. The chocolate mousse couldn’t be simpler to make, and I often prep everything ahead of time so the final assembly is quick and stress-free. It’s a beautiful, impressive dessert that’s sure to wow any crowd, especially the chocolate lovers in your life! Best of all, the combination of moist chocolate cake with creamy mousse filling is absolutely divine. It’s rich without being too heavy, and always a crowd favorite.
Try my other cake recipes, like Chocolate Cobbler, Carrot Cake, Flourless Chocolate Cake, or Dulce de Leche Cake!
How to make Chocolate Mousse Cake:
Bake Chocolate Cake: Mix sugar, flour, cocoa powder, baking powder, baking soda, and salt in a large bowl. Add eggs, milk, oil, and vanilla. Beat with a hand mixer on medium speed for 2 minutes, stir in boiling water and prepare into prepared pans. Bake at 350°F for 30–35 minutes. (A box cake mix can be used if you prefer).
Make Chocolate Mousse: Mix cocoa powder and hot water until smooth. Melt chocolate chips in the microwave or use a double boiler. Add cocoa powder mixture to the melted chocolate and stir until smooth. Let cool to room temperature. Whip the cream and sugar together in a large mixing bowl until very stiff peaks. Add cooled melted chocolate and gently fold the mixture together to combine. Refrigerate until you assemble the cake.
Assemble the Cake: Once cakes are cool, slice each in half horizontally with a sharp serrated knife to create four layers. Place one of the cake rounds on the serving tray then spread a thin layer of chocolate mousse over it. Top with the next cake layer then repeat with the chocolate mousse between all layers. Smooth any extra chocolate mousse over the outside of the whole cake as a “crumb” coat. Refrigerate cake for at least 30 minutes, or up to 1-2 days if it's covered well.
Make Frosting & Serve: Heat milk, cocoa, and butter in a medium saucepan. Bring to a boil then remove from heat and beat in powdered sugar with electric mixers to get rid of any lumps. Cool for 15-20 minutes, until pourable but not too warm that it melts the mousse. Pour and smooth over chilled cake. I like to use pieces of parchment papers gently under the edges of the cake to catch the frosting as it drips down. I usually pour it slowly and catch it as it comes down the sides and smooth it along the sides. Serve chocolate mousse cake once set.
Layered Chocolate Mousse Cake Recipe
Equipment
Ingredients
Chocolate Cake:
- 2 cups granulated sugar
- 1 3/4 cups + 2 Tbsp all-purpose flour
- 3/4 cup unsweetened cocoa powder
- 1 1/2 teaspoons baking powder
- 1 1/2 teaspoons baking soda
- 1 teaspoon salt
- 2 large eggs
- 1 cup buttermilk
- 1/2 cup oil, (vegetable or canola oil)
- 2 teaspoons vanilla extract
- 1 cup boiling water, , or hot coffee
Chocolate Mousse:
- 1/2 cup hot water
- 4 Tablespoons unsweetened cocoa powder
- 1 1/2 cups semi-sweet chocolate chips
- 2 cups heavy whipping cream
- 2 Tablespoons granulated sugar
Chocolate Frosting:
- 6 Tablespoons milk
- 3 Tablespoons unsweetened cocoa powder
- 1/2 cup butter, (one stick)
- 3 3/4 cups powdered sugar
Instructions
Chocolate Cake:
- Heat oven to 350°F. Grease and flour two 8 or 9 inch round baking pans. (I like to line the bottom of mine with wax or parchment paper).
- Dry ingredients: Stir together sugar, flour, cocoa powder, baking powder, baking soda and salt in large bowl.2 cups granulated sugar, 1 ¾ cups + 2 Tbsp all-purpose flour, ¾ cup unsweetened cocoa powder, 1 ½ teaspoons baking powder, 1 ½ teaspoons baking soda, 1 teaspoon salt
- Add Wet Ingredients: Add eggs, buttermilk, oil and vanilla; beat on medium speed of mixer 2 minutes. Stir in boiling water (the batter will be thin). Pour batter into prepared pans.2 large eggs, 1 cup buttermilk, ½ cup oil, 2 teaspoons vanilla extract, 1 cup boiling water
- Bake for about 30 to 35 minutes or until a toothpick inserted in the center comes out clean. Allow cake to cool in the pan for 5 minutes and then remove to wire cooling racks. Cool completely. (You could freeze the cake rounds at this point, if desired.)
Chocolate Mousse:
- Stir the cocoa powder and hot water together. In a double-boiler (or in the microwave) melt the chocolate chips, just until smooth. Add the cocoa mixture to the melted chocolate chips and stir well to combine. Allow to cool to room temperature.½ cup hot water, 4 Tablespoons unsweetened cocoa powder, 1 ½ cups semi-sweet chocolate chips
- In a separate large bowl, beat the cream and sugar until very stiff peaks form. Add the chocolate mixture and fold in with a spatula until well combined. Refrigerate until ready to use, up to 5 days.2 cups heavy whipping cream, 2 Tablespoons granulated sugar
Chocolate frosting:
- In a medium saucepan, add milk, cocoa, and butter. Bring to a boil. Remove from heat. Add powdered sugar and mix with electric beaters to get rid of any lumps. Allow to cool for 15-20 minutes, stirring occasionally.6 Tablespoons milk, 3 Tablespoons unsweetened cocoa powder, ½ cup butter, 3 ¾ cups powdered sugar
- Torte Cakes: Once cakes have cooled, use a sharp serrated knife to torte each cake (cut each cake evenly in half, horizontally, so that you end up with four, thin, 9'' cake pieces).
- Layer mousse: Place one cake layer on a serving plate. Spread a big spoonful of mousse on top of that cake layer. Repeat with the remaining cake layers, adding a layer of mousse filling between each layer of cake. Use remaining mousse filling to spread it evenly around the entire outside and top of the cake. Refrigerate for 30 minutes.
- Chocolate Frosting: (I usually make the warm chocolate frosting while the cake is in the fridge.) Remove cake from fridge and very slowly pour the cooled chocolate frosting over the top. Use a spatula or knife to gently spread the frosting evenly over the outside of the cake as you pour. Refrigerate until ready to serve.
Notes
- Mousse: Place in an airtight container in the fridge for up to 5 days. Fold it again gently with a spatula before using. But the texture is best the day of.
- Cake Rounds: These can be made in advance and frozen. Once baked, cool them completely and then wrap them in a double layer of plastic wrap. Place in a freezer safe bag and freeze for up to 3 months.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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*I first shared this recipe in May 2014. Updated May 2018, February 2022 and October 2025.
Made this for a friend and he says it’s the best cake he’s ever had. Thanks so much. Question, though….how do you keep a large amount of the frosting from puddling at the bottom on the cake board and instead staying on the cake?
Hi Mandy, I’m so happy to hear it! Next time, try to let the frosting cool a little longer before pouring it over the cake. That should help it not run down so much. It will probably pool a little bit however, so what I like to do is put a few scraps of tinfoil or wax paper underneath the edges of the cake before I pour the frosting on. Once the frosting has cooled a little bit you can pull the paper out (and the excess frosting with it). Hope that helps!
I am excited to try this recipe with the mousse filling! I made this cake last week in a 9×13 pan and tried to adjust for high altitude, but it still sunk in the middle a little. What would you suggest to adjust when baking at a high altitude? Will cooking it in 9″ pans fix the problem or do I still need to adjust the ingredients more?
Hi Kara, It shouldn’t matter what pan you bake it in. For high altitude I would suggest adding at least 1 or 2 tablespoons of extra flour. Also, try decreasing the sugar by 2 tablespoons, add a tiny bit less baking powder and soda than what is called for. That should help significantly!
Just made this for my Dad’s bday. The cake does not look pretty but I am hoping it will taste great! The icing did not seem to pour well and sorta displaced some of the mousse. Can’t wait to try it!
This cake is AH-MA-ZING!!! It’s a little extra work but absolutely worth it. Thanks for sharing. This ones going in the book!!
Thank you so much Sherry! I’m so happy you liked it!
I am making a wedding cake this week. Would the cake and mousse filling hold up as a bottom layer? The layer on top of it will be spice with cream cheese filling. I would love to use this recipe as the base.
Hi Sherry, I’m honestly not sure…what are you using to secure the cakes together? Dowels? Have you made this cake ever before? I fear it may be too soft/slippery to support another cake on top… I’d feel terrible if I encouraged you to go ahead with it and it didn’t work…
This recipe looks amazing! I’m planning on making it tonight. I have some left over chocolate cream cheese frosting. Do you think that would taste ok with this cake? Thanks so much! 🙂
Hi Amy, I’m sure your chocolate cream cheese frosting would taste amazing with it! Yum!
Hi,
Just wanted to know should avoid put baking powder if im using buttermilk? and should i use half the amount of baking soda…? you know,cz of the acidity in baking soda n all…
Thanks in advance!
Hi,,,,
just wanted to know if im using butter milk,should i leave the baking powder? and should i minimize the baking soda…
Thanks heaps!
Hi,
Im making this cake tomorrow for a birthday.. was wondering if i can use melted butter instead of oil and also if i could use buttermilk instead the milk???
Thanks!
Hi Pavi, I have tried using buttermilk and it works great. I haven’t used butter instead of oil, so I can’t say for sure, but I imagine it should work fine….I’d love to hear how it turns out!
Hi,
I am currently making this cake, it’s been more than 35 minutes but its still not cooked!
I’ve followed the recipe and I have doubled it in order to make 2 9-inch cakes..
Is this my mistake? I should have used the recipe you’ve mentioned and only separated it into two pans?
Please help!
Thanks 🙁
I have made this cake at least four times now. The first time was a disaster but it still tasted amazing!!! This is by far my favorite chocolate cake I’ve ever made or eaten. And the mousse is AMAZING beyond words!!!
Thanks so much! Sounds like you’ve perfected it!