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Chocolate Mousse Cake Recipe – From Scratch

Chocolate Mousse Cake combines layers of moist and fluffy chocolate cake spread with smooth and creamy chocolate mousse. Then the cake is covered in a perfect chocolate buttercream frosting for the ultimate intensity of chocolate in every bite.

Side view of a slice of a chocolate mousse layer cake on a plate - hostess at heart
Triple Chocolate Mousse Cake

This beautiful and decadent chocolate mousse cake will slay even the most serious chocolate craving with its rich, creamy filling. If you’ve been looking for the perfect recipe for chocolate mousse cake, this is the one!

Why You’ll Love This Chocolate Layered Mousse Cake

  • Simple to make. It looks quite fancy and is sure to impress your guests, but it is really quite easy to make following the step-by-step instructions.
  • Incredibly tasty. If you love chocolate, this cake is a must-have dessert that you will bring to the table over and over again. Make it your new family tradition.
  • Versatile. While I’ve made this chocolate cake with chocolate mousse filling, you can use this chocolate cake recipe with other fillings or just make bake it and frost it without layering it.
A tableview of a slice of chocolate cake with layers of chocolate mousse filling and frosted with chocolate buttercream. The sliced chocolate layer cake sits on a cake stand in the background. Hostess At Heart

Tools You’ll Need For This Recipe for Chocolate Mousse Cake

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Ingredients For Your Chocolate Mousse Layer Cake

Top down view of all of the ingredients used to make a chocolate cake and mousse filling. Hostess At Heart

Layered Chocolate Cake from scratch

  • Granulated Sugar.
  • All-Purpose Flour.
  • Cocoa Powder. The darker the cocoa powder, the darker the cake, mousse or buttercream will be. The look you’re going for dictates your choice.
  • Baking Powder. Used as leavening.
  • Baking Soda. Both are needed to give this cake its fluffy but moist texture.
  • Salt.
  • Eggs.
  • Buttermilk. If you don’t have any in the refrigerator, you can make your own buttermilk.
  • Canola Oil. If you need to substitute, use the most flavor-neutral oil you have.
  • Vanilla Extract.
  • Boiling Water. If you want a coffee flavor instead, use hot coffee.

Chocolate Mousse Ingredients

  • Hot Water.
  • Cocoa Powder.
  • Semi-Sweet Chocolate Chips.
  • Heavy Cream.
  • Sugar.

Chocolate Buttercream Frosting Ingredients

  • Milk.
  • Cocoa Powder.
  • Butter.
  • Powdered Sugar.

Please note, that the recipe card has more complete instructions. This is intended as an overview.

How To Make Chocolate Mousse Cake

Step 1: Prep

Heat oven to 350 °F and grease and flour two round 8” or 9” baking pans. Pull your ingredients out and double-check that you have everything on the list.

Step 2: Mix.

Stir together sugar, flour, cocoa powder, baking powder, baking soda, and salt in a large bowl. Add eggs, buttermilk, oil, and vanilla, then beat on medium speed. Stir in boiling water (it will be a thin batter). Pour batter into prepared pans.

Step 3: Bake the Chocolate Mousse Cake Recipe.

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 at room temperature.

Step 4: Make the Chocolate Mousse Cake Filling

Stir the cocoa powder and hot water together. In a microwave, melt the chocolate chips and stir until they’re completely melted and smooth. Add the cocoa mixture and stir. Cool.

In a separate mixing bowl beat the cream and sugar until very stiff peaks form. Add the chocolate mixture and gently fold it all together. Refrigerate.

Step 5: Make the Chocolate Buttercream Frosting.

In a medium saucepan, add milk, cocoa, and butter. Bring to a boil over medium-high heat. Remove from heat. Add powdered sugar and mix using the whisk attachment of your electric mixer on medium-high speed. Cool.

Step 6: Assemble the Chocolate Mousse Layer Cake.

Once the cakes have cooled, cut each cake evenly in half horizontally. Stack and spread each layer with the chocolate mousse.

Once the cake and each layer are covered in mousse, refrigerate it for 30 minutes. Then, very slowly, pour the cooled chocolate frosting over the top. Spread the frosting gently so as to not disturb the chocolate mousse. Refrigerate.

Popular Variations & Additions

  • For this recipe, I use a “boiled” chocolate buttercream frosting. You can use a no-cook buttercream recipe as well.
  • You could add a dusting of toasted and crushed walnuts or pecans to the top of this cake.
  • Use hot coffee for a fun, fresh twist on this amazing cake.

How To Store Chocolate Mousse Layer Cake

Best Way To Store Leftover Chocolate Layered Mousse Cake

Refrigerate this cake. Don’t leave it at room temperature for more than 2 hours. Refrigerate for up to 4 days, covered in an airtight container. The mousse will eventually get weepy.

Can I Freeze Chocolate Cake With Mousse Filling

No, I don’t recommend freezing this chocolate mousse cake. The mousse layer is full of air, making it light and fluffy. After you freeze it, the cake will not have a light and fluffy consistency and will dry out.

Side view of a chocolate mouse cake on a cake stand frosted with chocolate buttercream. A cake server sits in the front on a linen napkin placed over a serving plate.

Layered Chocolate Mousse Cake FAQs

Is mousse the same as pudding?

No. Unlike pudding, mousse isn’t cooked. Mousse is made by folding in whipped cream in this recipe.

Can Chocolate Cake With Mousse Filling be made ahead of time?

You can bake the cake 2 days before you assemble it with the mousse. Allow the cake to cool to room temperature and then wrap the layers in plastic wrap and refrigerate them.

You don’t have to slice the layers until you’re ready to assemble the cake and actually chilling the cake allows the cake to slice easier.

You can also make the buttercream frosting and the chocolate mousse up to 2 days in advance and store them separately in airtight containers. It’s best if you assemble it the day you want to serve it.

Tips for the perfect Chocolate Mousse Layer Cake

  • Do not overwhip the mousse. Overwhipping will separate the cream into butter, causing it to become grainy.
  • Lightly freezing a cake can make it easier to slice.
  • This cake doesn’t have to be a four-layer cake. Just add the filling between each cake for a two-layer cake.
  • This cake can be baked in 8-inch pans. The cake layers will be a little thicker. Or, in 9-inch pans. The layers will not be as thick but will be a little wider.
  • You can use a double boiler to melt the chocolate chips but I find that the microwave works best at 50% power and short increments. Stir between each increment.
  • When assembling the layers, put one rounded layer on top and gently slice the rounded top off of the second pan, and place it upside down on the pie plate. Not slicing the top flat can cause your cake to lean. I use a serrated knife for this step.
  • Adding a skim coat with a thin layer of buttercream and letting it set will help keep cake crumbs out of your final layer of frosting.
Slice of chocolate cake with layers of creamy chocolate mousse frosted with chocolate buttercream on a plate - Hostess At Heart

What to Pair with Your Chocolate Cake With Mousse Filling

For an after-dinner treat, pair this cake with a light-bodied pinot noir, a Cabernet Sauvignon, or your favorite coffee such as this Bailey’s Coffee.

Don’t Forget To Come Back And Let Me Know How your Chocolate Mousse Cake Recipe Turned Out!

A slice of chocolate frosted cake laying on it's side showing layers of a mousse filling - hostess at heart

Chocolate Mousse Cake

Author: Julie Menghini
Chocolate Mousse Cake combines layers of moist and fluffy chocolate cake spread with smooth and creamy chocolate mousse. Then the cake is covered in a perfect chocolate buttercream frosting for the ultimate intensity of chocolate in every bite.
5 from 4 votes
Prep Time 45 mins
Cook Time 35 mins
Total Time 1 hr 20 mins
Course Dessert
Cuisine American
Keyword: Chocolate Buttercream Frosting, Chocolate Cake
Servings: 12 servings

Ingredients
 
 

Chocolate Cake Ingredients

  • 2 cups granulated sugar
  • 1 ¾ cups flour plus 2 tbsp
  • ¾ cup cocoa powder
  • 1 ½ tsp baking powder
  • 1 ½ tsp baking soda
  • 1 tsp salt
  • 2 eggs
  • 1 cup buttermilk
  • ½ cup canola oil
  • 2 tsp vanilla extract
  • 1 cup boiling water or hot coffee

Chocolate Mousse Ingredients

  • ½ cup hot water
  • 4 tbsp cocoa powder
  • 1 ½ cups semi-sweet chocolate chips
  • 2 cups heavy cream
  • 2 tbsp sugar

Chocolate Buttercream Frosting

  • 6 tbsp milk
  • 3 tbsp cocoa powder
  • ½ cup butter softened
  • 3 ¾ cup powdered sugar

Instructions
 

Chocolate Cake Instructions

  • Heat oven to 350 °F and grease and flour two round 8” or 9” baking pans.
  • Stir together sugar, flour, cocoa powder, baking powder, baking soda and salt in large bowl.
  • Add eggs, buttermilk, oil and vanilla then beat on medium speed of mixer for 2 minutes.
  • Stir in boiling water (it will be a thin batter). 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.

Chocolate Mousse Cake Filling

  • Stir the cocoa powder and hot water together.
  • In a 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.

Chocolate Buttercream Frosting Instructions

  • 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.

Chocolate Mousse Cake Assembly Instructions

  • Once cakes have cooled, use a sharp serrated knife cut each cake evenly in half, horizontally, so that you end up with four, thin, 8” or 9” cake pieces.
  • Place your first cake layer on your cake serving plate or pedestal. 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.
  • 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. Enjoy.

Nutrition

Calories: 812kcalCarbohydrates: 106gProtein: 8gFat: 43gSaturated Fat: 21gPolyunsaturated Fat: 4gMonounsaturated Fat: 15gTrans Fat: 0.4gCholesterol: 97mgSodium: 443mgPotassium: 414mgFiber: 5gSugar: 83gVitamin A: 915IUVitamin C: 0.2mgCalcium: 115mgIron: 4mg

Nutritional Disclaimer

This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.

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Recipe Rating




Kathleen

Thursday 29th of December 2022

SO good! Made this for an after Christmas party we hosted, not a crumb was left!

Julie Menghini

Saturday 31st of December 2022

Thanks! It's such a delicious and easy cake to make.

Eliza

Thursday 29th of December 2022

I can't believe how easy this delectable chocolate mousse cake was to make. The flavors are incredible, and my whole family loved it!

Julie Menghini

Saturday 31st of December 2022

Thank you! This cake is our go-to easy chocolate cake to make.

Lynn

Tuesday 27th of December 2022

Decadent without being too rich! LOVED it!

Julie Menghini

Tuesday 27th of December 2022

Thanks, Lynn! Such an easy recipe for any occasion.

Healthy

Thursday 1st of December 2022

Julie this delicious cake is epic and love your helpful step by step instructions. We don't make desserts often but when we do we go big. We are going to add the coffee for a little kick.

Julie Menghini

Thursday 1st of December 2022

You are just as sweet as this cake! Thank you.