Chocolate Mousse Cake

 
Hi everyone! Sorry I haven't posted in so long. My computer was getting an OS update and I had to re-set up a lot of things on it.

This cake is not only 100% flour free, but one of the lightest and fluffiest chocolate cakes you'll ever eat. The version I made is a chocolate cake with coffee buttercream filling and chocolate ganache on the outside, but the possibilities are almost endless for the variations you could make with this cake. And if you feel uncomfortable with layer cakes, you could 1/2 the recipe and make one layer with frosting just on the outside. This isn't the prettiest cake, but it tastes amazing.

The buttercream pictured is actually Swiss meringue buttercream, not the French buttercream I'm including in this recipe. But since the Swiss is trickier to work with (it became slightly separated after having put it in the fridge then trying to remix it so that it would soften, even though it turned out perfectly at first) I think that the French would be easier when you're starting out. Regular American buttercreams are a no-go because they always contain confectioner's (powdered) sugar which contains the slightest bit of corn starch.

I made a 6 inch (in diameter) cake comprised of three layers of cake. I ended up having some batter left over which I made into cake pops. (I'll show you how to do some starch free cake pops soon!) But you could make this into an 8 inch cake with just two layers and it would be the perfect amount of batter.

Chocolate Mousse Cake
serves 8-10
10 ounces semisweet chocolate chips
1/2 cup unsalted butter, cut into pieces
8 eggs, separated --  (make sure the whites are completely free of yolks or oil, or they won't fluff up correctly -- also make sure that the whites are at room temperature before you mix them, they'll form stiffer peaks that way)
1/4 tsp cream of tartar
1 tsp vanilla extract

for the chocolate ganache:
1/2 cup heavy cream
4 ounces semisweet chocolate chips
1 tsp vanilla extract
2 Tbsp unsalted butter, softened

for the Coffee French Buttercream:
makes 2 cups
2 large eggs
1/2 cup granulated sugar
2 Tbsp instant espresso dissolved in 1 Tbsp warm water
pinch salt
16 Tbsp (2 sticks) unsalted butter, softened but still cool, each stick cut into quarters

For the Cake:

1. Preheat the oven to 350 degrees F. Lightly butter three 6-inch cake pans (or two 8-inch cake pans) and line the bases with buttered parchment paper rounds (cut out to fit each pan).

{lined cake pans}

2.  In a saucepan, melt the chocolate and butter (I would put the butter in the pan first to protect the chocolate from direct heat) over low heat until smooth, stirring frequently. Remove from heat and whisk in the egg yolks until completely blended. Beat in the vanilla extract and pour into a large bowl. Set aside, stirring occasionally.

3. In a clean, grease-free bowl, using an electric mixer, beat the egg whites slowly until frothy. Add the cream of tartar and increase the speed and continue beating until they form soft peaks, then stiffer peaks that just flop over a little at the top. Have patience, this will take 5-10 minutes.

{stiff peaks}

4. Stir a large spoonful of white into the chocolate mixture to lighten it, then fold in the remaining white until they're just combined. Don't overmix, or the whites will fall.

5. Divide batter between cake pans, smoothing the tops evenly and tapping the sides gently to remove any air bubbles. Bake for 30-35 minutes until puffed. The cakes will fall slightly when you take them out of the oven. Cool on a wire rack for 15 minutes, then use a knife to loosen the sides and invert the cakes onto the rack and remove the papers.

6. When completely cooled to room temperature, wrap up each cake layer in saran wrap and put into the fridge. Refrigerate for at least 2 hours before you assemble your cake.

For the Coffee French Buttercream:

1. Combine the eggs, sugar and salt in a mixing bowl and place the bowl over a pan of simmering water (but don't let the bottom of the bowl touch the water, this is called a double boiler). Whisking gently but constantly, heat the mixture until it's thin and foamy and registers 160 degrees on an instant-read thermometer.

2. Remove the bowl from the water and beat the egg mixture at medium-high speed until light, airy and cooled to room temperature, about 5 minutes. Reduce the speed to medium and add the butter, 1 piece at a time (it may look curdled halfway through, but it will smooth out with additional butter and mixing). After you've added all the butter, add in your dissolved coffee. After all the butter and coffee is added, increase the speed to high and beat 1 minutes, until light, fluffy and thoroughly combined. The buttercream can be covered and refrigerated for up to 5 days.

For the Chocolate Ganache:

1. Bring the cream to a boil in a heavy saucepan over medium-high heat. Remove the pan from the heat and add all the chocolate at once, stirring until melted and smooth. Stir in the vanilla and beat in the softened butter. Set aside for about 5 minutes before you use it so that it can thicken slightly. Ganache should coat the back of a spoon in a thick, smooth layer.

To assemble the cake:
Unwrap the cake layers and place one on a large flat plate. Using a piping or a spatula, dollop on the buttercream and spread it into a smooth layer, making sure that you put it over the edge, so that it squishes out a little between cake layers. Add your second layer of cake and repeat with the buttercream. Add your third cake layer and push down to flattened the cake, making sure that the buttercream is evenly spread out underneath the layers. Pour your chocolate ganache on top of the cake, letting it run down the sides and using your spatula to spread evenly over the sides of the cake. Then put the cake back into the fridge to set.

{hell yeah, chocolate cake!}

--Kara