Chocolate Mousse Layer Cake

I finished my last final today! Yaey. Well I don't have much more to say about that, so here is some yummy cake.

This cake was one of the two birthday cakes I made for my boyfriend. And it was definitely one of the more stressful cakes I've made because it involves layers of mousse in between cake (I was worried about the mousse deflating, which I think it did) and then the layered cake/mousse/cake/mousse is frozen, then you put a layer of hot chocolate ganache on top (and let it cool again). I was freaking out about the hot ganache melting the mousse, the mousse deflating, and to top that off I put the chocolate ganache on right before we were about to walk out the door (with the cake), not allowing the ganache to firm up with an immediate refrigeration. My boyfriend proved his love to me (or to the cake?) by keeping the windows open (it was cold out) to try and keep the cake cool, because he knew how worried I was about it on the 20 minute drive to drop it off in his brother's fridge.

Well, despite all of my freak outs, the cake was really awesome. Maybe the mousse was supposed to be lighter, but I loved the texture the way it was. In the photo of the unsliced cake, the ganache looks weird and clumpy because it's hot (and maybe I messed something up there), but it set up quite nice once refrigerated. Overall a really really good chocolate cake. Oh and did I mention that it has 17 ounces of chocolate?

If this sounds good, you might also like:
Chocolate Volcanoes
Sour Cream-Chocolate Cake with Peanut Butter Frosting and Chocolate-Peanut Butter Glaze
German Chocolate Cake
Rich Chocolate Cheesecake

Chocolate Mousse Layer Cake
Adapted from The Cake Book

Sour Cream Chocolate Cake
1 3/4 cups (212 g) all purpose flour
1 2/3 cups (332 g) granulated sugar
1/3 cup (28 g) natural (not Dutch processed) cocoa powder
1 tsp baking soda
1/4 tsp salt
2 large eggs
1/2 cup (121 g) sour cream
2 tsp vanilla extract
1/2 cup (4 oz) unsalted butter, melted and cooled
1/3 cup safflower or corn oil
3/4 cup ice cold water

Chocolate Mousse Filling
9 ounces (255 g) bittersweet chocolate, coarsely chopped
1/2 cup whole milk
1/4 cup (50 g) granulated sugar
1 tsp instant coffee powder
pinch of salt
2 tsp vanilla extract
1 cup heavy cream

Bittersweet Chocolate Glaze
6 ounces bittersweet chocolate, coarsely chopped
2/3 cup heavy cream
1 tsp vanilla extract

Classic Whipped Cream
1 1/2 cups heavy cream
3 tbsp (21 g) confectioners' sugar, sifted
1 1/2 tsp vanilla extract

Make the cake:
1. Position a rack in the center of the oven and preheat the oven to 350F. Grease the bottom and sides of a 9x3 inch springform pan. Line the bottom of the pan with a round of parchment paper, and grease the paper. Dust the paper and the sides of the pan with flour and tap out the excess.

2. Sift together the flour, sugar, cocoa powder, baking powder, baking soda, and salt into a medium bowl. Whisk to combine, and set aside.

3. In another medium bowl, whisk together the eggs until blended. Whisk in the sour cream and vanilla extract until blended. Set aside.

4. In the bowl of an electric mixer, using the paddle attachment, mix the melted butter and oil together at low speed. Add the cold water and mix to blend. Add the dry ingredients all at once and mix at medium-low speed for 1 minute. Add the egg mixture and mix for another minute, scraping down the sides of the bowl with a rubber spatula as necessary. Scrape the batter into the prepared pan.

5. Bake the cake for 45 to 50 minutes, until a toothpick inserted into the center comes out clean. Set the pan on a wire rack and cool the cake for 20 minutes.

6. Invert the cake onto the rack. Reinvert the cake and cool completely.

Make the chocolate mousse filling:
7. Place the chocolate in the bowl of a food processor and process until finely ground. (Leave the chocolate in the processor.)

8. In a small saucepan, combine the milk, sugar, coffee powder, and salt and bring to a boil over medium heat, stirring until the sugar dissolves. With the food processor running, pour the hot milk through the feed tube, and process until the chocolate is completely melted. Scrape down the sides of the bowl, add the vanilla extract, and process until blended. Scrape the mixture into a large bowl and let cool for 10 minutes.

9. In the bowl of an electric mixer, using the whisk attachment, beat the ehavy cream at high speed until soft peaks form. Using a rubber spatula, gently fold one-third of the whipped cream into the chocolate mixture. Fold in the remaining cream until completely blended. (The mousse should be used immediately.)

Assemble the cake:
10. Using a long serrated knife, trim off the domed top of the cake so taht the cake is perfectly level; reserve the tirmmings. Cut the cake horizontally into 2 layers.

11. Place one of the cake layers in the bottom of a 9x3 inch springform pan. Scrape half of the chocolate mousse over the cake layer and spread it into an even layer. Top with the other layer. Scrape over the remaining mousse and spread it into an even layer.

12. Cover the top of the pan with plastic wrap or foil and freeze the cake for at least 3 hours, until firm.

Make the whipped cream:
13. In the chilled bowl of an electric mixer, using the whisk attachment, whip the cream at high speed just until it begins to thicken. Add the sugar and vanilla and beat until soft peaks form. Use immediately, or cover and refrigerate.

Make the bittersweet chocolate glaze.
14. Place the chocolate in the bowl of a food processor and process just until finely ground. (Leave the chocolate in the processor.)

15. In a small saucepan, bring the cream to a boil. Remove from the heat and add the chocolate to the pan. Stir until the chocolate is completely melted and the glaze is smooth. Stir in the vanilla extract. Transfer the glaze to a small bowl. Let the glaze cool for about 10 minutes before using.

Glaze and garnish the cake:
16. Remove the cake from the freezer. Run a sharp thin-bladed knife under hot water and wipe it dry. Run the knife between the cake and the side of the pan to release the cake; reheat the knife as necessary. Remove the side of the pan. Using a small offset metal spatula, smooth the mousse of the sides of the cake.

17. Place the cake on a wire rack and set the rack over a baking sheet. Pour the warm glaze over the top of the cake and use the offset metal spatula to smooth it evenly over the top and sides. (Ashley note: I found it hard to "ice" so I just spread it and dripped it down the sides.) Refrigerate the cake for at least 1 hour (to thaw) before serving.

18. About 30 minutes before serving, remove the cake from the refrigerator. Cut the cake into wedges and serve with the whipped cream.