This is the perfect Chocolate Mousse Cake recipe. Soft and moist chocolate cake layer topped with super creamy chocolate mousse and soft chocolate ganache.
I provide you with a detailed recipe in the recipe card at the bottom of the page, a step-by-step video, and I cover the process of preparing the chocolate ganache, which you need for the chocolate mousse, more in-depth because that is the trickiest part and needs more explanation.
How to make a chocolate ganache
First, combine egg yolks, heavy cream, and sugar in a large saucepan and cook over medium heat until it thickens and coats the back of the spoon about 1-2 minutes. Do not boil at any time.
Then remove from the heat and continue whisking for about 1 minute. Then add the melted chocolate and whisk until fully combined.
It can happen that at this point in the recipe you face the problem that the chocolate splits, gets grainy, or you have an oily film on the surface.
Why did my chocolate ganache split?
This can happen when the chocolate was getting too fast too hot in the pan. So make sure that you remove the pan from the heat first, continue whisking, and then add the chocolate.
And now what? What is IF the chocolate really breaks? Do you need to throw everything away and start new? Generally, no.
If this happened to you, the first thing you should do is to grab your electric mixer and mix until it comes together. In most cases, this will work fine and saves your ganache. It will be smooth and silky again. You can also mix in 1 tbsp of corn syrup or honey to smooth it.
If this all didn't help, heat up heavy cream and stir it into the ganache little by little. Normally, this should help.
What is if your ganache is still broken? Well then you have to face the truth that the chocolate was way too hot, and you better do it again.
Did this ever happen to me? Of course! Multiple times. The most important thing: Don't throw away your nerves! And in most cases, you can fix it very easily.
And if not? Ok, that's bad because of the resources like food, money, and your time. But what should you do? What happened that happened. Go on and do it again. With practice, you get better, and you learn from mistakes.
I found a great source to read around that topic. How to fix a broken ganache.
If you did everything right (or fixed it) the ganache will look like in the picture below.
This Chocolate Mousse Cake is
- extremely creamy
- out-of-this-world chocolatey
- a great dessert for every season
- beyond delicious
As you can see I sprinkled the cake with grated chocolate. Too much chocolate you think? Nope. Highly recommended. Also recommended are berries on top. They are a perfect fit for this cake.
If you make this Chocolate Mousse Cake recipe leave a comment, rate it and tag a photo #alsothecrumbsplease on Instagram! Would love to see your snap!
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The Chocolate Mousse Cake Recipe
Ingredients
Chocolate mousse
- 3 cups heavy cream, divided (720ml)
- 8 large egg yolks
- 1/4 cup granulated white sugar (50g)
- 3 cups semi-sweet chocolate, melted (525g)
- 3/4 cup powdered sugar, sifted (90g)
Chocolate cake layer
- 1 cup all-purpose flour (120g)
- 3/8 cup dutch-processed cocoa powder (32g)
- 3/4 cup granulated white sugar (150g)
- 1+1/2 tsp baking powder
- 1/2 tsp salt
- 1/4 cup vegetable or canola oil (60ml)
- 1 large egg
- 1/4 cup buttermilk (60ml)
- 1 vanilla bean* (or 1 tsp vanilla extract)
- 1/4 cup hot cocoa (60ml)
Chocolate glaze
- 1 cup semi-sweet chocolate, finely chopped (175g)
- 3/4 cup heavy cream (180ml)
Instructions
- Make the Chocolate Mousse: In a medium saucepan, whisk together 1+1/2 cups heavy cream, egg yolks, and sugar and cook over medium heat for about 1-2 minutes until it coats the back of a spoon. Do not boil at any time. Remove from heat and continue whisking about 1 minute. Add melted chocolate and whisk consistently. Transfer to a bowl and let cool completely. If your chocolate ganache breaks, then read the blog post above to know how to fix the ganache easily.
- Preheat oven to 350°F/175°C. Line the bottom and the sides of a 9" / 23cm baking pan with parchment paper. Set aside.
- Make the chocolate cake layer: In a medium bowl combine flour, cocoa, sugar, baking powder, and salt and stir to combine. Set aside. In a large mixing bowl with a stand or handheld mixer fitted with a whisk or paddle attachment, beat oil, egg, buttermilk, and vanilla* just until combined. Stir in dry ingredients to combine. Slowly mix in hot cocoa until combined. The batter will be thin. Transfer batter to the prepared baking pan. Bake for 16-18 minutes or until a toothpick in the center comes out clean. Don't overbake. I baked mine for 18 minutes. Let cool in the pan for about 20 minutes. Then open the springform pan and let cool to room temperature.
- Continue with the Chocolate Mousse: With a handheld or stand mixer fitted with a whisk attachment, whisk 1+1/2 cups heavy cream until soft peaks form. Add powdered sugar and whisk until stiff peaks form. Stir about 1/4 of whipped cream into the cooled chocolate cream with a whisk. Then gently fold in the remaining whipped cream with a wooden spoon.
- Assemble the cake: Cut a thin layer off the top of your cake to create a flat surface. Close the springform pan again. Spread the chocolate mousse evenly on top of the cake layer. Chill overnight in an airtight container in the fridge.
- Make the chocolate glaze: Place chopped chocolate in a large heatproof bowl. Place heavy cream in another heatproof bowl and microwave until very hot, almost boiling for about 1-2 minutes. Pour over chocolate and let stand 1-2 minutes. Whisk until smooth, and the chocolate is completely melted. Let cool in the fridge for about 10-15 minutes that it thickens. Test the consistency of the glaze down the side of the bowl. It should drip. The longer it stands, the thicker it gets. If it is too firm, re-warm it a few seconds in the microwave. Once it reached the desired consistency, it's ready to spoon on top of the cake.
- Remove cake from the fridge and spoon the glaze little by little around the sides and let drip off the sides. Do this with a small spoon and do one drip at the time. Then spoon or pour the rest of the glaze on top of the cake (maybe you don't need all) and level with an offset spatula. Place cake in the fridge for 15 minutes that the glaze gets firm if needed. Decorate with grated chocolate and berries if desired or to your preference. Store leftovers in an airtight container in the fridge up to 3 days.
I tried your recipie it was amazing and delecious but the problem was that the mouse was not firm enought and it didnt stand much what could be the problem ?
I'm so sorry! I think that there could be two reasons. First, the chocolate ganache was maybe too liquid because it was not cooked until thick enough. Or the whipping cream was not stiff enough when folded in. Please make sure to fold the whipping cream carefully into the chocolate ganache that you don't lose all the air.
Just wondering how far in advance can I make the mousse? This looks amazing, btw. Thank you!
The mousse should be done when the cake is baked and chilled. The mousse needs to be poured on top of the cake right after you made it. Because the mousse gets firm in the fridge you would not be able to pour it on top of the cake once it's chilled.
Just what I was looking for., thank you. I was wondering how this freezes? I'm making it for a friend that just wants a piece at a time.
Although it won't be as delicious as fresh, it is possible to freeze single cake slices. Therefore, place the cut slices into to freezer for about 1 hour until firm enough to wrap it in plastic foil tightly. Wrap it twice and make sure everything is covered. Then place the wrapped slices in freezer bags and squeeze out as much air as possible. The cake slices freeze well up to 1 month. For thawing, unwrap the slice and place in the fridge in an airtight container to thaw overnight. As said before, it won't be as delicious as fresh because the cut surfaces and the ganache dry out during the freezing and thawing process. Hope that helps!
This cake looks incredible, almost too beautiful to eat! Huge congratulations on the PDN award, I clicked over to check out your winning photo, it’s BEAUTIFUL!!
Thank you so much, Nicole! I'm happy that you like it. Thank you so so much!!
The recipe calls for 1/4 cup hot cocoa. I’m confused where this is made or where we obtain this. Please clarify.
The hot cocoa is hot water and unsweetened cocoa powder made according to the instructions on the cocoa powder package but without sugar. I used 1/4 cup hot water and added 1 tbsp cocoa.
Hi Sabine! Do you serve this cold or room temperature. Excited to try it tomorrow. It’s currently chilling in the fridge 🙂
Hi Natalie, I serve it cold out of the fridge. But you can try to place one slice on the kitchen counter for 30-60 minutes before serving to find out how you like it the most 🙂 Happy holidays!
VERY GOOD I LIKE THANCK YOU
Thank you so much!
Made this for the christmas potluck party and it was a hit! I reduce the sugar and it still work pretty well! Love this recipe!
Kayla, I'm super happy that it was a hit! Thank you so much for your feedback!
Oh my good gracious. Please, everyone. You must check out this amazing recognition of achievement Sabine has received: http://www.shutterloveonline.com/contest_galleries/taste/2018/#main. I remember commenting on this very masterpiece she created and it took top prize! Sabine, if you won a monetary prize, I know it was not enough. What you do is priceless. CONGRATULATIONS! Now I know I have been in correspondence with a real super-star.
Awww, Amanda. You are always so nice! Thank you so much! I won a small prize but this is not important to me. I'm just amazed that I got picked by such top judges. And no. No. I'm definitely not a superstar at all. I'm just a regular girl with a passion for food and food photography 🙂 Have a great day!
Congratulations, Sabine! That you are being recognized amid millions of daily bloggers says so much about your creativity, ingenuity, talent, intelligence, and hard work ethic. I am amazed by you and I will be watching your video above once again to see the moment when you pour the mousse layer into the pan:) I know you are leaving for New York soon, and I thought maybe you could try the famous Brooklyn Blackout Cake when you are here (https://www.bonappetit.com/recipe/blackout-cake). I have a feeling that this mousse cake of yours beats all others though. I hope you have a fantastic Halloween, followed by your trip to the U.S., and if your blogging/photography skills are going to be part of your job when you move here, please let me know. You have so much talent, I can't wait to see what you do with it when it is unleashed here in San Francisco.
Thank you so much, Amanda! I really appreciate your ongoing support. It means so much to me. Speaking of pouring the mousse into the pan. I bet you would love to be the pan at that moment as much as I do, right? 😉 The Brooklyn Blackout Cake is something that is on the top of my baking list for a long time. I need to bake it soon. Happy almost Halloween!
Now I know what I am going to be for Halloween--a pan! Take care, Sabine, you gifted and talented super-human.