Dark Chocolate Mousse Cake

Dark Chocolate Mousse Cake

Three layers and three textures of dark chocolate goodness in one indulgent dark chocolate mousse cake!

My love affair with chocolate since the beginning

Since I can remember, I love chocolate!

I was a lucky child because there was always a chocolate cake with fudge in our kitchen. This fact made me quite popular at school and with neighbourhood friends, who used to pop by to hang out and enjoy a piece of soft, moist and fudgy chocolate cake.

The better chocolate – dark

Dark chocolate has less sugar than white and milk chocolate therefore, I only eat dark chocolate. I love to have a couple of pieces of 99% cacao chocolate, which is quite bitter but satiates my cravings for sweets. However, for desserts, I like to use 70% cacao chocolate. It is dark and for my taste, it has the right amount of sugar.

The inspiration for this dark chocolate mousse cake

Some days ago, I went to one of my favourite Italian restaurants in London and this time we ordered the chocolate mousse cake instead of the tiramisu – for a change.

The chocolate mousse cake was amazing, fresh and creamy on the inside, with a beautiful chocolate sponge cake as a base. This delight inspired me to make my version of this cake. I already have a great French chocolate mousse recipe on the blog. I also have a great Peruvian chocolate sponge cake recipe – the one they used to bake at home when I was a child. I decided to add a third layer, a dark chocolate ganache, which I learned how to make at Le Cordon Bleu Paris. So, this succulent cake has three recipes that result in a fresh yet indulgent chocolatey experience. 

Dark chocolate mousse cake recipe in four easy steps

Use a 30cm diameter round mould

Step 1 – Make the chocolate sponge cake (about 1.5 cm high)


¾ cup whole wheat flour

½ cup brown sugar

¼ tablespoon baking powder

¼ cup unsweetened cocoa powder

½ heaping teaspoon baking soda

½ teaspoon salt

1 egg

½ cup milk

½ tablespoon white vinegar

½ cup vegetable oil (grapeseed oil is a good neutral choice)

¼ teaspoon vanilla essence


  • Preheat the oven at 180 degrees C or 350 degrees F.
  • Grease a round mould of 30 cm diameter and cover the bottom with baking paper.
  • Sift the flour 3 to 4 times. This will add air to the mix and will result in a lighter sponge cake.
  • Pour the white vinegar into the milk and let sit.
  • Sift once into the bowl with flour, the other dry ingredients: brown sugar, baking powder, unsweetened cocoa powder, baking soda and salt.
  • Add the vegetable oil to the sifted dry ingredients and mix well with a spatula until it becomes a uniform batter.
  • Add the milk with vinegar and mix.
  • Add the egg and mix.
  • Finally, add the vanilla extract and mix well.
  • Pour the mixture in the round cake mould and place it in the middle of the preheated oven at 180 degrees C or 350 degrees F.
  • Bake for 10-15 minutes. Start checking after 10 minutes.
  • Let cool in the mould for five minutes.
  • Carefully unmould and put on a rack to cool down while you make the French chocolate mousse.
Chocolate sponge cake cooling in a rack
Dark chocolate sponge cake cooling in a rack

Step 2 – Make the French chocolate mousse


200 gr good quality dark chocolate; I used 70% cacao

8 eggs, yolks and whites separated

¼ cup non-dairy milk or regular milk if you prefer. I used oat milk.


  • Melt chocolate and non-dairy milk in ‘bain-marie’ or water bath in low heat. The water should be simmering and not boiling. The water shouldn’t touch the base of the bowl on top.
Chocolate and milk in hot water bath
Chocolate and milk in water-bath
  • When melted, remove from the heat and introduce the egg yolks one by one and mix. The result should be homogeneous and shiny.
add eggs one by one
Add egg yolks one by one
  • Beat the egg whites to stiff peaks. 
  • Add egg whites to the chocolate little by little and mix delicately with a spatula.
carefully mixing beaded whites to chocolate mousse mix
Carefully mixing whites into chocolate mousse mix

Step 3 – Make the dark chocolate ganache


200 gr cream

200 gr good quality dark chocolate; I used 70% cacao

¼ teaspoon vanilla extract


  • Boil cream and vanilla.
  • Place chocolate pieces in a bowl.
  • Add half of the boiling mix to the chocolate and wait until it melts.
boiling cream into chocolate pieces
Boiling cream into dark chocolate pieces
  • Use a whisk to mix the chocolate only in one spot.
  • Add the rest of the cream and mix. 
  • For the perfect texture, use an electric hand mixer to make a perfectly homogeneous ganache.
Use a hand mixer to get the perfect ganache texture
Use a hand mixer to get the perfect ganache texture
  • Let cool in a tray until soft and creamy.

Step 4 (final step) – Assemble the chocolate mousse cake

  • Remove the baking paper from the sponge cake.
  • Once the chocolate sponge cake has cooled down cut the dome (if any) to have a straight sponge cake layer.
  • Place the sponge cake back into the round mould and lightly press it down to. Have an even layer.
  • Pour the chocolate mousse on top and tap the mould a few times to get rid of any air bubbles.
Sponge cake and mousse in the mould
Sponge cake and mousse in the mould to cool in the fridge overnight
  • Cover the top of the mould and refrigerate overnight.
  • Unmould the cake and pour the chocolate ganache on top allowing it to fall a little bit on the sides.
  • Make the ganache before decorating and serving the cake. If you make it in advance, heat it in ‘bain-marie’ or water-bath and cool it down until you get a good texture to pour on top of the cake.
  • Decorate with chocolate shavings or unsweetened cocoa powder (optional).
cake with shiny ganache on top
Cake ready to be cut and enjoyed


  • Serve the cake chilled, right out of the fridge to avoid the sponge cake base become too humid.
  • Make sure the ganache is cool but not too cold, therefore, solid. The perfect texture will be a shiny and thick creamy chocolate ganache.
a slice of cake with the three layers showing
A delicious piece of dark chocolate mousse cake

Find more sweet recipes here

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