Chocolate Chocolate Mousse Cake
A chocolate lover's dream cake. A light chocolate chiffon cake forms the base, then a fluffy layer of chocolate mousse, and finally a dreamy dark chocolate ganache tops off this amazing cake.
Ingredients
Chocolate Chiffon Cake Layer
- 1/2 cup Cake flour or all-purpose (70g)
- 3 tablespoons Cocoa powder (Dutch processed) (20g)
- 1/3 cup + 1 tablespoon Sugar (83g)
- 3/4 teaspoon Baking powder
- 1/4 teaspoon Salt
- 3 large Eggs separated
- 1 1/2 tablespoons vegetable oil
- 3 tablespoons water
- 3/4 teaspoon instant coffee powder
- 3/4 teaspoon vanilla extract
- 1/4 teaspoon cream of tartar
Chocolate Mousse Layer
- 2 1/4 cups heavy cream (divided)
- 5 oz Semi-sweet dark chocolate chopped (140g)
- 4 oz milk chocolate chopped (113g)
- 2 tablelspoons water
- 2 3/4 teaspoons gelatin
Chocolate Ganache Layer
- 5 oz semi-sweet dark chocolate chopped (140g)
- 2/3 cup heavy cream
- 1 tablespoon corn syrup if using
Instructions
Chocolate Chiffon Cake
- Preheat the oven to 340F.Line the bottom of a 9” spring form pan with parchment paper then tighten up the sides of the pan so that there is excess paper hanging out the bottom. Cut the excess off with scissors. Set the pan aside.
- In a large mixing bowl sift together the 1/2 cup flour and 3 tablespoons of cocoa. Stir in 3/4 teaspoon baking powder, 1/4 teaspoon salt, and 1/3 cup + 1 tablespoon of sugar until combined. Set bowl aside.
- In another mixing bowl stir together the 3 tablespoons of water and 3/4 teaspoon of instant coffee powder. Stir in the rest of the wet ingredients: 3 egg yolks, 11/2 tablespoons vegetable oil, and 3/4 teaspoons of vanilla. Add the contents of the wet ingredient bowl to the dry ingredient bowl and stir to combine without over mixing.
- In a medium mixing bowl, make sure it is clean and dry (see note 4). Add the 3 egg whites and 1/4 teaspoon cream of tartar. Using a mixing stand or hand mixer, beat the egg whites until stiff peaks form (see note 5).
- Scoop 1/3 of the beaten egg whites into the cake batter mixture and stir gently to combine. Then scoop the next 1/3 of beaten egg whites into the cake batter and fold in very gently with a rubber spatula. Finally, scoop the remaining egg whites into the batter bowl and gently fold in again with a rubber spatula.
- Pour the cake batter into the prepared springform pan. If you have a cake strip follow the manufacturer's instructions which is usually to soak in water and wrap around the cake pan. See note 6.
- Bake at 340F for 18-20 minutes. Cake is done when a toothpick comes out clean. You might want to start checking at 16 minutes.
- Let cake cool in the springform pan on a cooling rack for 30 minutes
Chocolate Mousse
- Heat the 3/4 cups of heavy cream in a saucepan until just below a simmer. Pour the hot heavy cream overtop of the chopped dark and milk chocolate in a mixing bowl. Allow to sit for 3-4 minutes and then stir until all the chocolate has melted into a homogenous mixture. If all the chocolate hasn't melted you can place in the microwave for 10 seconds and stir again. If necessary you can heat again for another ten seconds until fully melted. Set the bowl aside.
- Sprinkle 2 3/4 teaspoons of gelatin over the 2 tablespoons of water in a small bowl and allow it to hydrate for two minutes. Then heat the small bowl in the microwave for 15 seconds and stir until completely dissolved. If necessary you can give it another 10 seconds in the microwave if it needs it.
- Stir the gelatin mixture into the melted chocolate mixture until fully incorporated. Allow to cool with intermittent stirring, about 15 minutes.
- While the chocolate mixture is cooling, prepare the springform pan with an acetate cake collar or parchment paper. Start by running a knife around the edge of the cake to loosen it, then release and remove the springform ring. Lift the cake out, discard the parchment paper from the bottom, and place the cake back into the base of the springform pan. Wrap an acetate collar around the cake and secure the springform ring back in place. If you don’t have an acetate collar, use parchment paper instead, wrapping it around the entire edge of the cake so it extends at least to the top of the pan or slightly above. Set the prepared pan aside.
- Once chocolate mixture has finished cooling for about 15 minutes, you can begin to whip your cream. Add the 1 1/2 cups of heavy cream to an empty mixing bowl and beat to firm peaks. Scoop about 1/3 of the whipped cream into the chocolate mixture and gently stir it in. Scoop another 1/3 of the whipped cream and very gently fold it in with a rubber spatula. Add the rest of the whipped cream and again gently fold in with a rubber spatula. See Note 7.
- Pour/scoop the mousse onto the top of the chocolate cake in the prepared springform pan. Use the back of a spoon or rubber spatula to evenly spread the mousse over the top of the cake. Cover with plastic cling wrap and place in the fridge to set for at least 4 hours or overnight.
Chocolate Ganache
- Chop the chocolate and place in a pyrex measuring cup if you have one, or a heat proof bowl.
- Heat 2/3 cup of heavy cream in a small saucepan with stirring just before it comes to a simmer. Pour the hot cream over the chocolate and allow it to sit for 4 minutes. Stir the cream and chocolate together until it becomes a homogenous smooth mixture.
- Stir in the 1 tablespoon of corn syrup.
- Allow the ganache to cool for 25 minutes with intermittent gentle stirring. Pour the ganache over the cooled chocolate mousse layer tilting the cake to allow the ganache to coat evenly.
- Return the cake to the fridge to allow the ganache to cool and set, for at least 2 hours.
- Once the ganache has set you can remove the acetate collar or parchment paper (see note 8), slice, serve, and enjoy.
Notes
- You can sub all-purpose flour for cake flour if you do not have it. Cake flour has a lower gluten content and produces a lighter airier crumb, but I have made this with all-purpose flour too and the results really were just as good.
- If you don't have instant coffee powder, but you do brew coffee at home, you can replace the coffee powder and 1/8 cup water with 1/8 cup of brewed coffee. The coffee helps to bring out the chocolate flavour. If you don't want to add coffee you can also delete it, and just add 1/8 cup of water.
- Corn syrup helps to make the chocolate ganache shiny, but can be deleted if you don't have it.
- In order to beat egg whites to stiff peaks, your bowl and beaters must be totally free of any oil residue and preferably no water. Any oil present will prevent the eggs from whipping properly. Also it is best to use a glass or metal bowl as plastic bowls can have an oil residue.
- You know you have beaten your egg whites to stiff peaks when you lift the beater out and the egg whites stand straight up.
- Cake strips are soaked in water and prevent the formation of a dome on your cake. This is merely for appearances as it keeps the cake layer straight. You could also just slice off the dome after the cake has cooled.
- When adding the whipped cream to the chocolate mixture, you want to fold it in gently to maintain as much of the airiness as possible so the final mousse is light and fluffy. You also don't want to add the whip cream when the chocolate mixture is too warm or it will melt and your mousse will be more dense.
- I find the ganache to be quite soft and pulls away a bit with the acetate collar. You can just run the back of a knife or offset spatula around the cake to clean up the ganache layer at the end.