This easy Chocolate Mousse Cake features a box of cake mix that’s deliciously dressed up with a thick layer of chocolate mousse and decadent ganache. It’s a simple yet stunning chocolate cake that’s so easy to make!
What’s in this Chocolate Mousse Cake Recipe
Box cake mix is layered with chocolate mousse and thick ganache… Each indulgent layer of this chocolate cake is easy to make with simple ingredients!
- Devil’s Food Cake Mix: Any brand works well! Pick your favorite.
- Vegetable Oil: Canola oil is a fine substitute if needed.
- Egg: You’ll need one egg and a separate egg yolk.
- For the Chocolate Mousse
- Powdered Plain Gelatin: This is what gives the mousse that perfect consistency.
- Chocolate Chips: You can use semi-sweet, dark, or milk chocolate chips in your mousse. The choice is yours!
- Heavy Cream: Heavy cream can NOT be substituted with whole milk, or anything else for that matter. Don’t even try it!
- Powdered Sugar: This helps with both the sweetness and the consistency of the mousse.
PRO TIP: Devil’s food cake or just regular chocolate cake are both great box mixes to use for this recipe.
How can I garnish this cake?
Berries, chocolate shavings, and so much more can be used to garnish this gorgeous cake! You could always pipe some extra mousse on top of the cake before serving, too.
You sure can! Use your favorite chocolate cake recipe, or try my personal favorite homemade Devil’s food cake recipe!
If you only have gelatin leaves on hand, you can use 2 leaves of gelatin in place of the 2 teaspoons of powdered gelatin.
If your mousse turns out a bit runny, it’s probably because the whipped cream was not stiff enough before you incorporated the chocolate and gelatin mixture. Avoid this issue by whipping the cream until stiff peaks form.
How to Store
In an airtight container in the fridge, chocolate mousse cake will stay fresh for up to 3 days.
Serve this mousse cake recipe on a holiday like Valentine’s Day! It’s also great for anytime you’re craving some luscious chocolate flavor.
More Chocolate Cake Recipes We Love
- Chocolate Pound Cake
- Chocolate Fudge Cake
- Chocolate Raspberry Cake
- Brownie Cake
- Chocolate Strawberry Cake
- Chocolate Peanut Butter Cake
Chocolate Mousse Cake Recipe
For the Cake
- 7⅝ ounces Devil's food cake mix 216 grams, such as Betty Crocker (½ box)
- ⅝ cup water 142 grams
- ¼ cup vegetable oil 50 grams
- 1 large egg 50 grams
- 1 egg yolk 14 grams
For the Chocolate Mousse
- 2 teaspoons powdered plain gelatin 6 grams
- 2½ tablespoons cold water 35 grams
- 2¼ cups chocolate chips 383 grams
- 3 cups heavy cream 681 grams, divided
- ½ cup powdered sugar 57 grams
For the Ganache
- ⅔ cup heavy cream 151 gams
- 8 ounces chocolate chips
- Chocolate shavings optional, for garnish
- Fresh berries optional, for garnish
For the Cake
- Prepare ½ package of cake mix according to the instructions on the box. The above ingredient measurements are for ½ box of Betty Crocker Devil's Food Cake, so be sure to use halved measurements for the appropriate ingredients if you use a different brand of cake mix. If your cake mix calls for 3 eggs, use 1 egg and 1 egg yolk as your halved measurement. Bake in a 9-inch springform pan according to the instructions (around 25 minutes) and let cool on a wire rack while you prepare the mousse.
For the Chocolate Mousse
- In a small bowl, combine the gelatin and cold water and bloom for 5-10 minutes.
- Meanwhile, place chocolate chips in a heatproof bowl. In a small saucepan set over medium-high heat, bring 1 cup of heavy cream to a simmer (between 112-115°F), then remove from the heat.
- Whisk in the bloomed gelatin and stir until completely dissolved. Pour mixture over the chocolate chips and whisk until melted and combined. Allow mixture to cool, stirring occasionally.
- In the bowl of a stand mixer fitted with the whisk attachment, or with a hand mixer in a large bowl, beat the remaining 2 cups of cream with the powdered sugar until stiff peaks form.
- Stir about ¼ cup of the whipped cream into the melted chocolate. Gently fold in the remaining whipped cream until fully incorporated.
- Spread the chocolate mousse evenly on top of the cooled cake while still inside the pan.
- Cover with plastic wrap and refrigerate for at least 8 hours or up to overnight.
For the Ganache
- Once the cake has chilled overnight, place the chocolate chips in a heatproof bowl. In a small saucepan set over medium-high heat, bring 1 cup of heavy cream to a simmer (between 112-115°F), then remove from the heat.
- Pour the warm cream over chocolate chips and allow to sit for 3-4 minutes, then whisk gently until smooth and shiny. Allow to cool until slightly thickened, then pour over the mousse.
- Cover and chill for 1 hour. Serve garnished with chocolate shavings and berries, if desired.
- Your mousse needs time overnight to sit before the ganache is poured on top. Do not try to rush this process!
- Devil’s food cake or just regular chocolate cake are both great box mixes to use for this recipe.
- Heavy cream can NOT be substituted with whole milk, or anything else for that matter. Don’t even try it!
- Nutritional information does not include optional ingredients.