The Easiest Chocolate Mousse Cake
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This decadent Chocolate Mousse Cake is a copycat Costco cake that starts with a simple boxed cake mix. It is a rich and velvety chocolate cake that is layered between chocolate mousse that is a chocolate lover’s dream and the perfect dessert for holidays or special occasions.
I am obsessed with the Chocolate Mousse Cake from Costco. It’s literally any chocolate lover’s fantasy. Fluffy layers of moist chocolate cake filled with smooth and decadent chocolate mousse and covered with chocolate cream frosting and chocolate cookie crumb.
I’m literally drooling as I write this. That’s how much I love that cake.
But what I love even more is that I can make this same cake at home, and make it easily with a simple boxed cake mix. But the final result is so glorious, it’s the perfect showstopper dessert for any holiday gathering or special occasion.
Why Try This Chocolate Cake Recipe
- Delicious – Chocolate lovers are sure to love the rich chocolate flavor of this decadent layer cake.
- Easy Recipe– Because this shortcut recipe starts with a box cake mix, it saves you some time.
- Festive – This easy chocolate cake with creamy chocolate mousse filling is the perfect dessert for any holiday or special occasion.
Chocolate Mousse-Filled Cake Ingredients
This rich chocolate cake uses simple ingredients for absolutely glorious results.
Fudge Cake Ingredients
- Fudge Cake
- Unsalted butter – softened at room temperature
- Milk
- Eggs
Whipped Chocolate Frosting Ingredients
- Powdered sugar – or confectioners sugar
- Unsweetened cocoa powder
- Butter
- Vanilla extract
- Corn syrup
- Semisweet chocolate chips‘
Chocolate Mouse Cake Filling Recipe Ingredients
- Chocolate cake mix – I use a 13.5 oz box mix for this recipe, not the 15 oz package
- Heavy Cream
Equipment Needed To Make Chocolate Cake with Mousse Filling
- Large mixing bowl
- Electric mixer or stand mixer
- Round cake pans
- Wire rack
- Piping bag (optional)
Substitutions & Alterations
- You can add crushed or chopped nuts to the top of the whole cake
- Sprinkle mini chocolate chips over the top of the cake or add them to the mousse. You could also use chocolate shavings or drizzle more melted chocolate for a chocolate ganache style topping.
- After the cake has cooled but before you add the mousse, spread a layer of cherry or raspberry jelly or preserves on the part of the cake around the mousse. (That’s the top of the first layer and the bottom of the top half.)
- At Costco, the outside of this cake has a chocolate crumb coating. You can achieve the crumb coating by crushing up chocolate cookies very finely and pressing the crumbs into the side of the cake. Again, you can also use chocolate shavings.
How to Make Chocolate Mousse Cake
This is a Step by Step Instructions overview – Full recipe instructions are in the recipe card below.
Step 1 – In a large bowl, add cake mix and package ingredients. Mix over medium speed.
Step 2 – Divide the cake batter evenly between 2 cake pans.
Step 3 – Bake for 20 minutes or until a toothpick inserted in the middle comes out clean. Let cakes cool on wire rack.
Make the Chocolate Mousse Filling. Add pudding mix and heavy cream.
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Step 4 -Beat on high with mixer.
Step 5 – Remove one layer from pan and invert on plate.
Step 6 – Frost with layer of mousse filling
Step 7 – Add second cake layer and set aside. Prepare the Whipped Cream Frosting
Step 8 – Whip Cream Frosting ingredients.
Step 6 – Assemble the whole cake. Frost with frosting.
Step 10 – Add piping on edge and add cookie crumbles to side of cake.
Time Saving Tips & Tricks for the Best Chocolate Mousse Cake
- Be sure that cake has completely cooled before frosting it.
- Use a boxed chocolate mousse mix instead of making it from scratch.
- Use a can (or two) of whipped chocolate frosting instead of making your own.
- I recommend melting the chocolate in the microwave for ease, but you can also use a double boiler.
- Use a knife dipped in hot water to cut the cake so that the chocolate cake layers don’t get crushed.
- Use the whisk attachment if using a stand mixer instead of hand mixer
- Store leftovers in an airtight container in the refrigerator for up to 3 days.
How to Serve this Triple Chocolate Cake
This chocolate mousse cake is a standout dessert centerpiece perfect for any holiday meal, potluck or party, or just because it’s Wednesday.
- Serve this delicious cake with a scoop of vanilla or chocolate ice cream.
- Top each slice with fresh whipped cream and fresh berries
How to Store Chocolate Mousse Cake
Store leftovers in an airtight container in your refrigerator for up to 3 days. I like to place a piece of parchment paper or plastic wrap over the exposed areas where it’s been sliced so they don’t dry out.
You can also freeze extra cake for up to 2 months. I like to freeze pre-sliced pieces instead of the entire cake. Allow the frozen cake to thaw completely at room temp or in the fridge before serving.
More Reader Favorite Chocolate Dessert Recipes
Old-Fashioned Chocolate Coca Cola Cake
Chocolate Mousse Cake
Equipment
- 2 round cake pans
Ingredients
- 1 box Chocolate fudge cake mix 13.5 ounce
- 3 Eggs
- Butter the amount of oil the cake mix calls for
- 1/4 cup Milk the amount of water the cake mix calls for
Mousse Filling
- 3 cups heavy whipping cream
- 1 5.9 oz box instant chocolate pudding mix
Frosting
- 1 cup butter softened
- 2 cups powdered sugar
- 1 cup unsweetened cocoa powder
- 1 teaspoon vanilla extract
- ½ cup corn syrup
- 4 cups semisweet chocolate chips
Instructions
Making the Chocolate Cake
- Preheat your oven to 350 degrees.
- In a large bowl add your cake mix.
- Add the eggs your cake mix calls for plus one extra.
- Instead of the oil the box mix calls for add that much melted butter.
- Instead of the water the box mix calls for add milk.
- Whisk your cake mix until combined.
- Grease two 9 inch cake pans.
- Pour ½ batter into each cake pan.
- Bake for 20 minutes or until a toothpick inserted in the middle comes out clean.
- Cool the cakes completely.
Chocolate Mousse Cake Filling
- In a large bowl combine your heavy whipping cream with the dry instant pudding mix.
- Using an electric mixer, beat until combined and fluffy.
- Assemble your cake.
- Place down one cooled cake layer.
- Add all the mousse.
- Top with the remaining cake layer.
Make the Chocolate Whipped Cream Frosting
- In a microwave-safe bowl in 30 second intervals melt your chocolate chips with the corn syrup.
- Set aside to cool but not harden.
- Next in a large bowl using an electric mixer whip together the butter, powdered sugar, cocoa and vanilla.
- Whip until soft peaks form.
- Beat in the cooled chocolate mixture.
- Frost the cake sides first, then the top.
- Using a piping bag or plastic bag with the tip cut off and pipe around the edges.
- Use a fork to make squiggly lines across the top.
Notes
Nutrition
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Oh that really looks incredible!
Oh wow, that mousse does look so tempting.
Thank you for sharing and participating at SSPS 339. See you at #340
This was really delicious – will make again!