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.
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Recipe
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
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*I first shared this recipe in May 2014. Updated May 2018, February 2022 and October 2025.
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That cake looks so yummy! I would like to try your recipe.
If I’m making this the night before, serving the next day, would it be okay to make it all including the warm frosting on top then store in the refrigerator for the night?
Hi Lauren, I would suggest adding the frosting, letting it cool, and then flash freezing the cake (stick it in the freezer for about 15 min.) before covering it. Then cover it well with plastic wrap and tinfoil. I would suggest sticking it back in the freezer overnight (Ive never tried it in the fridge but I’m sure it would be fine too…)
I think I will give this a try this weekend. One question though, do I let the chocolate part of the mousse cool before adding the whipped cream? I would be afraid it may break it down.
I live to bake and at church the youth are always thrilled when I sign up to bake for a gathering. Thanks for sharing such great ideas!
Hi Jill, you definitely don’t want the chocolate part to be hot–wait til it’s just warm or close to room temperature but not hardened.
This is good to know about the mousse as some new bakers may not know to let it cool. Suggestion to add to the recipe instructions to let the mousse cool before adding to the whip cream 🙂 I’m sooo looking forward to this mousse. My chocolate is cooling now! Thanks so much! 🙂
I totally didn’t let it cool!! 🙁 Now it seems really soupy…will it thicken up after cooling in the fridge? Thank you! Tastes really good, though lol 🙂
The same thing happened to me. 🙁 I don’t know what to do. The recipe does not tell you to let it cool first. For us bakers who follow recipes to a T – you should probably add. I’m going to pray it hardens a bit in the fridge.
Hi Danielle, I apologize–I’ve updated that in the recipe!
I made this today, its sooooooooo delicious! I’ll definitely make again! Thank you!
Thanks Christy, soo glad you liked it!
Hi! Making this right now… After the cake has cooled, it is very sticky. Should I have used wax
or parchment to help take it out of the pan? Some of it stuck to the bottom even after I generously buttered and floured. It also stuck to my hands as I tried working it out of the pan… What am I doing wrong? Thanks! 🙂
Hi Andrea, what type of pan are you using? If it’s not a nonstick pan I would definitely put wax paper on the bottom, and then also spray well with cooking spray…
Hi! I used 2 non-stick 9″ rounds. I am making it again today, I will use parchment for sure. This is the best chocolate cake I’ve ever made….and it lasted perfectly in the fridge for a week, covered in wax paper. DELISH!!
So happy you liked it! Thanks Andrea!
The cake is delish! But the frosting was too thick. I added another half stick of butter and more milk. I think you may have made an error in one of the ingredients above. Maybe the milk?? I don’t know, but either way, it is very good.
Thanks so much, I love to hear that you liked it! I did adjust the frosting ingredients so it should be perfect now! Thanks for your comment 🙂
Awesome recipe! 🙂 I made this today ~ followed the instructions carefully – the frosting didn’t pour out but I was able to spread it on the cake & it tasted great. I followed the ingredients & instructions carefully — any tips (cut back on powdered sugar? maybe do 3C instead of 3 3/4C?) it looks delicious though – can’t wait to try a piece!! 🙂
Hi Tina, thanks for your comment and input! Glad you liked it!
I Can’t wait to try another recipe off your blog …. I love to bake. I thank my grandma for endless days of sitting on her huge island as a child while she baked almost daily … such a great creative outlet and the outcome is always (well, usually) De-Lish! lol 🙂
I just made this tonight it’s amazing, however my frosting did not pour out? It was still good just didn’t look pretty because it didn’t pour. I can’t figure out what I did wrong. Any suggestions I followed the recipe.
I’m glad you liked it! As far as the frosting–it’s always been pourable for me, so that’s weird… Next time I would try adding a little less powdered sugar, and don’t wait for it to cool 5min–just pour it right over!
WOW! This looks so amazing! Talk about chocolate heaven. Thanks for sharing!
Lauren, this is AMAZING. It looks like the infamous chocolate cake from Matilda where poor Ralphie has to consume!
Hahahaha it totally does! And, it was made with my “sweat and tears”! 😉 I think normal people would have been grossed out by that scene but it always made me crave chocolate cake! haha
I’m the same way! It was disgusting but I always craved chocolate cake once the scene was over!
Oh my goodness, this is making my mouth water! Looks so moist and flavorful! Pinning!
It’s seriously amazing!! Hope you get a chance to make it!
Hi! I ‘d just like to find out whether it would be possible to make the chocolate frosting before hand and then reheat it (perhaps over a double boiler) once I decide to ice the cake?
Hi there, that should be fine–refrigerate it until ready to frost them cake. You could heat it on low power slowly in the microwave or on the stove–add a tiny bit of extra milk if you need to, but once it’s barely smooth and stir-able you should be able to frost the cake easily. Good luck!
Thank you, that’s a huge help!! 🙂