Easy chocolate mousse cake recipe makes a moist dark chocolate cake that’s topped with a simple, easy chocolate mousse. Easy homemade cake recipe that always gets rave reviews!
I like chocolate mousse anything – Chocolate Mousse, French Silk Brownies, and chocolate mousse brownies are just a few of the chocolate mousse treats that I love! So it isn’t surprising that this chocolate mousse cake is one of my favorite cake recipes!
This cake is moist and intensely chocolaty. It’s topped with a super rich and creamy chocolate mousse for the ultimate chocolate dessert.
And all of that chocolate in one little piece of cake means a super delicious dessert that’s perfect for birthdays, holidays, or any time you want something a little extra!
“The absolute best chocolate cake I’ve ever made. I used 2% because I didn’t have buttermilk. The mousse was incredible. I’ll definitely be make this over and over.” – Jessica
Ingredient notes and substitutions
- Cocoa powder: I use regular unsweetened cocoa powder in this recipe. I’ve also used Hershey’s special dark cocoa powder. However, I haven’t tried Dutch-processed cocoa powder with this cake.
- Salt: If you don’t have kosher salt, use 1/2 teaspoon table salt instead.
- Buttermilk: Regular or low-fat will work. If you don’t have buttermilk, you can make a quick substitute with this recipe.
- Oil: Feel free to use another type of neutral oil like canola oil or olive oil.
- Water: I use hot tap water about (150F).
- Semisweet baking chocolate: If you’d like a sweeter mousse, you can use milk baking chocolate.
- Milk: Any milk from skim to whole milk will work.
How to make chocolate mousse cake
Here you’ll find step-by-step photos showing how to make this recipe. The full recipe, including ingredients, is given below.
Step 1: In a medium bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt. Set aside.
Step 2: In a large bowl, whisk together buttermilk and vegetable oil. Whisk in eggs one at a time.
Step 3: Stir in dry ingredients until just combined.
Step 4: Add hot water and vanilla. Whisk until just combined.
Step 5: Pour batter into prepared baking dish.
Step 6: Bake until wooden toothpick inserted in the center comes out clean. Cool to room temperature.
Step 7: To make the chocolate mousse, add mini marshmallows, chocolate, and milk to a large, heavy saucepan.
Step 8: Cook over low heat, stirring constantly, until melted and well-combined. Remove from heat, and cool completely.
Step 9: In a large bowl, beat whipping cream and vanilla together to soft peak stage.
Step 10: Fold whipped cream into cooled chocolate mixture.
Step 11: Spread over cooled cake. Chill for at least 30 minutes, or until ready to serve.
Recipe Tips!
- Metric: You can the weights for the ingredients by clicking on “metric” immediately above the ingredients.
- Grated chocolate: I grate a little chocolate over the top of the cake for looks and a bit of texture.
Recipe FAQs
This recipe has had hundreds of comments and questions. Here are some answers to some of the most commonly asked questions.
You can! The cake freezes well. Once the baked cake has cooled to room temperature, wrap it tightly in plastic wrap and then wrap it in aluminum foil. The cake will keep for up to 1 month in the freezer.
No, you can’t taste the marshmallows in the mousse. They help to make it light and fluffy, but it tastes like chocolate, not marshmallows.
The cake keeps well in the fridge. You can make it up to 1 day before serving and store it in the refrigerator.
Tips for making whipped cream
If you haven’t made whipped cream (or would just like some tips), I have lots of tips and more pictures here.
Storage
The cake can be stored, covered, in the refrigerator. It will keep for up to 5 days when properly stored in the fridge.
More chocolate cake recipes!
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Chocolate Mousse Cake
Equipment
- 9×13-inch metal baking pan
Ingredients
Chocolate Cake
- 1 ¾ cups all-purpose flour
- 1 ¾ cups granulated sugar
- 3/4 cups unsweetened cocoa powder
- 2 teaspoons baking soda
- 1 teaspoon baking powder
- 1 teaspoon kosher salt
- 1 cup buttermilk
- 1/2 cup vegetable oil
- 2 large eggs
- 2 teaspoons vanilla extract
- 1 cup hot water not boiling
Chocolate Mousse
- 1 ½ cups mini marshmallows
- 8 ounces semisweet baking chocolate chopped
- 1/2 cup milk
- 2 cups cold heavy whipping cream
- 1/2 teaspoon vanilla extract
Instructions
Chocolate Cake
- Preheat oven to 350 F. Grease a 9×13-inch baking pan. Set aside.
- In a medium bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt. Set aside.
- In a large bowl, whisk together buttermilk and vegetable oil.
- Whisk in eggs one at a time.
- Stir in dry ingredients until just combined.
- Add hot water and vanilla.
- Whisk until just combined.
- Pour batter into prepared baking dish.
- Bake 30-40 minutes, or until wooden toothpick inserted in the center comes out clean.
- Cool to room temperature.
Chocolate Mousse
- To make the chocolate mousse, add mini marshmallows, chocolate, and milk to a large, heavy saucepan.
- Cook over low heat, stirring constantly, until melted and well-combined.
- Remove from heat, and cool completely.
- In a large bowl, beat whipping cream and vanilla together to soft peak stage.
- Fold whipped cream into cooled chocolate mixture.
- Spread over cooled cake.
- Chill for at least 30 minutes, or until ready to serve.
- Refrigerate any leftovers.
Video
Notes
- Cocoa powder: I use regular unsweetened cocoa powder in this recipe. I’ve also used Hershey’s special dark cocoa powder. However, I haven’t tried Dutch-processed cocoa powder with this cake.
- Salt: If you don’t have kosher salt, use 1/2 teaspoon table salt instead.
- Buttermilk: Regular or low-fat will work. If you don’t have buttermilk, you can make a quick substitute with this recipe.
- Water: I use hot tap water about (150F).
- Semisweet baking chocolate: If you’d like a sweeter mousse, you can use milk baking chocolate.
- Milk: Any milk from skim to whole milk will work.
- Nutrition facts are estimates.
Nutrition
Did You Make This Recipe?
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Originally published 10/14/16. Post is updated regularly with new photos, tips, and information.
Cake portion adapted from Food Network.
Reader Interactions
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Comments & Reviews
Mary says
When you say baking chocolate for the mousse do you mean like the unsweetened baking bars? I make a chocolate recipe for thanksgiving every year because my daughter doesn’t like the traditional desserts. This will be the recipe this year 😊
Kate says
Hi! No, the semisweet baking chocolate would be the bars of semisweet baking chocolate that are sold near the chocolate chips in the grocery store. They should be right next to the unsweetened chocolate baking bars on the shelf. I’ve used Ghirardelli semisweet baking chocolate and Baker’s semisweet chocolate baking bar in this recipe, and they’ve both worked well.
Please let me know if you have any other questions, and happy Thanksgiving!
Tabatha says
I made this tonight and it was delicious. Is there a way to sweeten the chocolate mousse? I love dark chocolate but hubby likes things overly sweet. Can I add sugar to the whipped cream?
Kate says
Thank you! Yes, you can use milk chocolate instead of semisweet chocolate in the mousse. You could also add some sugar to the whipped cream like you would if you were making sweetened homemade whipped cream.
RUTH PARSONS says
Love it. It’s delicious. Can you make cupcakes and reduce the oven time?
Kate says
Thank you! I haven’t made this recipe into cupcakes, but I would guess that it would work. The baking time and temperature for cupcakes is usually 350F for about 18-25 minutes.
Olga Figueroa says
This cake is Delish, made it twice, it’s a keeper, thanks
Kate says
Thank you!
Diane says
Thank you so much for this recipe. It was a hit at my barbecue. My grandson loved it so much. He wanted me to make this his birthday cake., well I’m making it again this weekend. My grandson turns 20. What a wonderful recipe.
Kate says
Yay!! I’m so glad to hear that! Happy birthday to your grandson!
Dolores Samora says
I’m definitely gonna have to make this chocolate mousse cake 🎂 can’t wait
Olga Figueroa says
It’s Delicious, just made it again this weekend
Kate says
Thank you!
Carmen says
Kate,
Thank you for sharing this recipe. I love it so much. I made it a few times already and everyone raves about it. The moist is perfect and the lightness of the mousse is awesome. Is it possible to make a vanilla cake as well?
Kate says
I’m so glad that you’ve enjoyed the recipe! You could pair the mousse topping with a vanilla cake.
Gaylene says
My daughter made this for my birthday in May and now she wants it for her birthday tomorrow ❤️
Kate says
Yay! Happy birthday to your daughter!
Mel says
This was amazing and so easy to make! I used cane sugar, coconut oil for the vegetable oil, dark roast coffee in place of water and Dutch processed cocoa powder. It turned out incredible! Flavour and texture are perfection. It wasn’t too sweet or rich. 10/10 and will be my new go-to chocolate cake recipe.
Kate says
Thank you!
Carmen says
Hi Kay, after reading one of the comments asking if you can taste the marshmallows and your answer was “no”, as I am not a fan of marshmallows as well. I decided to try it. I have to say you are right, you cannot taste the marshmallows. This cake is amazing, everyone loved it. Thank you for sharing your recipe.
Kate says
Yay! I’m so glad that you liked the cake!
Dolores Samora says
I’m definitely gonna have to make this chocolate mousse cake 🎂 can’t wait
Kiley B says
Can you taste the marshmallow in the mousse?
Kate says
No, the mousse doesn’t taste like marshmallows.
Kiley B says
Thank you for the response! Making it for a friend who loves mousse but doesn’t like marshmallows so I wanted to check!
Susan Lostetter says
Am I able to make this into a layered cake with the mousse in between the layers? I’d like to make this for a birthday.
Kate says
I haven’t made it as a layer cake. The mousse is pretty soft, but it sets up well in the fridge. If you wanted to try making a layer cake, I would recommend frosting the first layer and then chilling it to let it set up before adding the second layer. I hope that helps!
Elii says
Hi there. Could I make the cake a week before and freeze it and put on the icing the day before my event?
Kate says
Hi! Yes, the cake freezes well, so that shouldn’t be a problem.
Kristi Locke says
This is absolutely delicious!! My house smells heavenly!!
Kate says
Thank you!
Barbara says
We made this cake for Father’s Day and it turned out so well! Everyone loved it. The mousse topping on the moist chocolate cake was a perfect combination. (Decided we could just make the mousse for a dessert sometime). This recipe was easy to make. A keeper!!
Kate says
Thank you!
Jessica says
The absolute best chocolate cake I’ve ever made. I used 2% because I didn’t have buttermilk. The mousse was incredible. I’ll definitely be make this over and over.
Kate says
Thank you!
Colette says
Can I make the mousse a day ahead of time? Or can I frost the cake the day before and refrigerate?
Kate says
The mousse is easier to use when it is freshly made, but you could frost the cake and refrigerate it.
Sandy says
Can I use gluten free flour
Kate says
Hi! I haven’t used that in this recipe, but I would guess that a measure-for-measure gf flour would work. If you give it a try, I’d love to hear how it turns out!
Aubrey says
Love love love!!! This has become a family staple at any get together!! I substituted the semi sweet for milk chocolate and oh my gosh! Game changer!!!!!
Kate says
Thank you!