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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!
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.
I Just made this today and though the cake turned out fabulous, the mousse just turned really thin and dripped everywhere. I refrigerated it before using and it still was thin. the cake slid everywhere as i was stacking it, do you know how to fix that?? Everything tasted great, but the mousse was just really runny. Do you have any tips?? I would really appreciate it.
Thanks!
Hi Adeela, I’m glad you liked it–sorry the mousse didn’t set up for you! My guess is that one of two things happened: Either you needed to beat the heavy cream more (make sure you reached “stiff peaks”). , or you added the whipped cream to the chocolate when the chocolate was too hot. The hot chocolate mixture could have softened the whipped cream too much, making the mousse thin…Do either of those sound like they could have happened?
BTW ~ Even though my cake wasn’t exceptionally beautiful (I’ll be tweaking a few things when I make it again) it is absolutely Delicious! The Mousse and frosting make this cake! I’ve made the Hershey chocolate cake before but your add-ins definitely bump it up to 5 stars!!! Love LOVE Love! 🙂
Hi Lauren, I prefer to use butter rather than oil. Can you please tell me how much butter I would need to replace the oil. Would it be ok to use butter or will it effect the recipe? Thanks
Hi Lara, I’ve never replaced the oil with butter so I can’t tell you exactly how it will turn out. You would substitute 1/2 cup of butter for the 1/2 cup of oil, but the method to making the cake would need to change. You would need to cream the butter and sugar together at the beginning (rather than adding the sugar into the dry ingredients). Like I said, I’m not sure how it will effect the end result, but let me know if you try it!
Hi Lauren ! I am making this cake on Sunday for my aunty, where you wrote the amount for flour did you mean 1 cup AND 3/4 or did you mean between 3/4 to 1cup of flour?
I hope you can get back to me in time, thank you
Hi Kelli, it’s 1 and 3/4 cup flour. Sorry for the confusion! Hope you enjoy it 🙂
Can I use cake flour for this recipe or does it have to be All purpose flour?
Hi Wendy, I think cake flour will work fine 🙂
I make this chocolate cake all the time….. found the original recipe on the back of the Hershey’s cocoa powder container…. can’t wait to try it with your frosting and mousse filing.
Hi there! This looks delicious! Can the mousse filling be used as a mousse topping on cupcakes? Can it be piped and hold its shape?
Thank u!
Hi Aneesa, yes, the mouse should hold its shape well. You can refrigerate it for 15-30 minutes (covered) before piping it, and then return the cupcakes to the fridge before serving. Sounds yummy!
I am making my sister shower cake in a few weeks and decided to do a trial run of the mousse. I am not impressed with the taste. Way too much chocolate! Any suggestions on how to turn down the chocolate flavor?
Hi Paula, you could try milk chocolate chips. You could also cut down on the amount of chocolate and increase the amount of whipped cream so the chocolate flavor was more mellow. Help that helps!
First time in my life I have ever heard of something as being too chocolaty!!! LOL! Well, in my world anyway. If I could eat chocolate for breakfast, lunch, and dinner I would! Can’t wait to make this!
I have made this cake twice now and it is the best chocolate cake recipe. I do have issues with my warm icing being too runny but it tastes amazing!! Thank you for the recipe!
This was chocolate heaven! Best chocolate cake I’ve ever had! The frosting ran down the sides a bit too quickly so I may let it cool longer next time but besides that, it was amazing! My new go to chocolate cake! Thanks for the recipe!
It really is chocolate heaven! Thanks for your comment–glad it turned out great!
Hello, so I made this cake for our anniversary and it was AMAZING! You are AMAZING, thanks for sharing this yummy recipe! =) I do however need more experience dividing the cake in half, maybe next time I’ll just divide and bake it in 1/4 and that way I wouldn’t have to cut it! Will this work and would I need to adjust the baking time/temp? =)
I’m soo glad you liked it! You wouldn’t need to adjust the temp, but I would adjust the baking time to be less!