Elegant, moist and delicious Chocolate Mousse Cake recipe filled with an easy homemade chocolate mousse, and warm chocolate frosting poured on top.
Want more cake recipes? Try my German Chocolate Cake, Berry Cake, or Coconut Cake with Pineapple Filling!
Why I love this easy mousse cake:
- Prep Ahead – The chocolate mousse recipe couldn't be easier to make, and you can prep everything in advance!
- Elegant – Fancy enough to impress any guests, especially a chocolate lover!
- Delicious – The chocolate cake is moist and divine. The chocolate mousse filling is creamy and pairs perfectly with the cake. This will become your new favorite cake!
How to make Chocolate Mousse:
Make the Mousse: Start by mixing the cocoa powder and hot water together until smooth. Melt chocolate chips in the microwave, or using a double boiler. Add the cocoa powder mixture to the melted chocolate and stir until smooth. Allow to cool to room temperature.
Whip the cream and sugar together in a large mixing bowl until very stiff peaks. Add the cooled melted chocolate and gently fold the mixture together to combine. Refrigerate until ready to use.
How to make Chocolate Mousse Cake:
Bake Chocolate Cake: Stir together sugar, flour, cocoa powder, baking powder, baking soda, and salt in a large bowl. Add eggs, milk, oil, and vanilla. Beat on medium speed for 2 minutes. Stir in boiling water then pour into prepared pans. Bake at 350 degrees for 30-35 minutes, or until a toothpick inserted comes out clean. (If you don't want to make the cake from scratch, you can use a box cake mix).
Halve the Cake Rounds: Once the cakes have cooled use a sharp serrated knife to torte them in half, lengthwise, so you have four thin layers of chocolate cake.
Stack Cake with Mousse Filling: Place the first cake layer on your serving tray. Smooth a thin layer of chocolate mousse over it, and top with the next layer of cake. Repeat to assemble a cake with chocolate mousse between each layer. Smooth any extra chocolate mousse you have over the outsides of the entire cake to make a”crumb” coat to seal the cake.
Refrigerate the cake for at least 30 minutes (or up to 1-2 days, covered) while you make the chocolate frosting.
Make Frosting: Combine milk, cocoa, and butter in a medium saucepan. Bring to a boil then remove from heat. Add powdered sugar and mix with electric beaters to get rid of any lumps. Cool for at least 15-20 minutes, stirring occasionally. Be sure to allow the frosting to cool long enough. You want it soft enough to still be “pourable” but you don't want it to be so warm that it melts the mousse into a puddle.
Pro Tip: Lay pieces of parchment paper around, and gently under the edges of the cake to catch the frosting as it drips down. I usually just pour the frosting slowly and catch it as it comes down the sides of the cake, smoothing it along the sides of the cake.
Make Ahead Instructions:
- Chocolate 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.
More Desserts to Try:
- Chocolate Peanut Butter Cake
- Meringue Roulade
- Chocolate Milkshake
- S'mores Bars
- Panna Cotta
- Tres Leches Cake
- World's Best Peanut Butter Bars
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Recipe
Chocolate Mousse Cake
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).
- Stir together sugar, flour, cocoa powder, baking powder, baking soda and salt in large bowl.
- 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.
- 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.
- 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.
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.
Assembly:
- 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).
- Place your first cake layer on your cake 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.
- (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 and February 2022.
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Also, what other tools are necessary for the recipe? Is an electric mixer needed to mix the ingredients for the cake batter?
This is fantastic! Not only tasty but so quick and easy to make.
Hi there,
Can you please provide me the chocolate mousse recipe in grams and ml?
Many thanks!
Oh my Lord!!! I have been truly blessed with your recipe!! I made this cake for my daughter and daughter-in-law’s b’day and Easter it is amazing!! I the cake with the mousse mostly because hubby saw the bar of chocolate and started to eat it until he realized it wasn’t sweet!! LOL!! what a face….couldn’t be mad at him. To make matters worse I was missing about 1/4 cup of cocoa and hubby was gone in the car – the neighbors are all gone – and no stores around! but I fudged it with some hot coco mix and can’t even tell. As I was frosting the cake, I took a couple of licks and ohhh!! is ever good…can’t wait to finish it off with some chocolate eggs. I saw there is also a carrot cake (my son’s favorite) sadly son in law and grandkids are lactose intolerant (so they claim) so cream cheese is out, I make cupcakes for them!!! LOL!!
thanks for the recipe!
So happy you liked it so much! Thank you for your sweet comment!
Hi, I know you posted this last year but I saw that some of your family is lactose intolerant. My sister in laws are too and we’ve made this dairy free cream cheese frosting for our carrot cakes and it’s delicious. You can hardly tell the difference. You can find dairy free cream cheese in the natural section of the store or at your local natural store.
Thanks for sharing this wonderful cake recipe. I love cakes and i am going to try this at home! Greetings from india!
I tried this cake and it tasted awesome however the cake was too soft that I couldnt cut in between to apply the filling. Any tips to make it cuttable? I appreciate your response
I always freeze my cakes (wrapping them really well) before I frost them. It makes cutting and frosting any cakes REALLY easy! 🙂
Looks very delicious. Next week is my son’s birthday and I am going to try it. Mine is not a very big oven and hence I am planning to bake it in two batches to make a 4 layered cake. Can the mixed ingredients stay at room temperature while one set bakes? Or should I refrigerate it?
I would keep the ingredients at room temperature in between baking! Good luck–sounds like fun! 🙂
Hi Lauren, Love the look of this cake.I’m from the UK and was wandering if you Would know the measurements in grams/ounces?Thanks in advance x
Okay like the author I too wanted to make my own birthday cake. This sounded like the one I wanted. So I decided, perfect, I’m going to do this one. The cake came out fine enough, cut it into large layers . Now for the mousse filling. Got the chocolate part done . Now for the whipping cream part.I got the heavy cream in the mixer and started mixing and got to medium speed and went to get the next step ready. Well now comes the iinteresting part. The wife comes in to “see” how its going ,comes over to the mixer and says “oh you need to turn this up faster” and she does. We bicker then I go back to doing what I was doing. It gets thicker, she keeps mixing . Then I hear “oh no it went back to liquid.” Guess what happens next . I go to the bowl and voila she has gone to far and now we have butter and liquid. I never knew you could do that . So I tried to recover it and decided to make the best of it, because the next steps were mute. So I mixed this heavy cream “butter” mix into the chocolate chip mix and put it on the layers. “At this point what have I got to lose.” The cake has just taken a new turn. No frosting. This fiasco is now over. So I put it in the fridge over night. This cake turned out to be so moist and delicious the next day. Incredible. Not the same recipe I wanted but delicious just the same. I am going to remake retry it the correct way and teach my wife how to whip heavy cream. But she loved the first way as well. We may have run into something here. Great recipe. And loads of fun
Hahaha–thanks for sharing your experience Darryl. It made me smile–and I’m sure glad it tasted great in the end!
Freeze the bowl and the beater for faster whipping! Promise it works great.
Lauren, this is the best chocolate cake I’ve EVER eaten! My daughter and I made this today for a friends birthday cake. IT WAS A M A Z I N G!!!
Thank you so much for sharing this recipe! I’ve saved it in my bookmarks, pinned it on Pinterst, and shared it Facebook!
This will be our “go to” chocolate cake from now on!
Hi Dee, I absolutely love to hear it! I’m so happy you all liked it so much! And thank you so much for sharing, and commenting 🙂
I made this cake yesterday. The cake and the mousse are both good, but the icing has to go!
I think the cake would have been fine with just the mousse, the icing seemed to ruin it for me.
Sorry.
Hi Nanette,
I’m sorry you didn’t like the frosting. It is actually one of my favorite frosting recipes. Everyone has different tastes :).