Sponge Cake with Custard Filling and Chocolate Ganache
Makes one 8-inch double layer cake
This cake is a combination of several recipes. My plan was to make a Boston cream pie, but it only partially resembles that favorite from my childhood with a custard filling and chocolate glaze. Nonetheless, it is a delicious dessert that is appropriate for a family dinner or special occasion. You can make the custard the day before you make and assemble the cake since it needs to chill for at least two hours.
- 1/3 cup granulated sugar
- 1/4 cup all-purpose flour
- 1/8 teaspoon salt
- 1 cup milk
- 1 large egg
- 1 teaspoon vanilla
- 1-1/2 cups sifted cake flour
- 1-1/2 teaspoons baking powder
- 1/2 teaspoon salt
- 3 large eggs, room temperature, separated
- 1 cup granulated sugar
- 1/3 cup water
- 1 teaspoon vanilla
- 8 ounces bittersweet chocolate (can use semisweet)
- 1 cup heavy cream
For the custard, mix the sugar, flour and salt in a medium saucepan. Stir in 3/4 cup of the milk. Bring to a boil over medium heat, whisking constantly. Cook for another 2 minutes. Remove from heat. Whisk together the egg and remaining milk, then whisk that mixture into the saucepan. Return to heat and cook just until it starts to boil, about 1 minute. Remove from heat and stir in the vanilla. Transfer to a bowl; cover with plastic wrap directly on the surface of the custard. Chill for at least 2 hours, or overnight.
For the cake, preheat oven to 350° F. Line the bottom of two 8-inch round cake pans with wax or parchment paper. Sift the flour, baking powder and salt onto a piece of paper or into a small bowl. In a medium bowl, beat the egg whites until soft peaks form. Add 1/2 cup of the sugar and beat until stiff peaks form. In a large bowl, beat the egg yolks and remaining 1/2 cup sugar until thickened and pale in color, and a ribbon forms when dropped from a spoon. Beat in the water and vanilla just until combined. Fold in the egg whites. Fold in half the flour until well incorporated, then repeat with the remaining flour. Transfer equal amounts of batter to each pan. Bake for 20-25 minutes, or until a tester inserted in the center of the cake comes out clean. Place the pans on a cooling rack for 20 minutes. Remove cakes from pans and let set until completely cooled, about 30 minutes.
Meanwhile, make the ganache. Break up the chocolate into a medium bowl. Heat the cream in a small saucepan just until it starts to bowl. Pour into the chocolate and stir until the chocolate melts. Let cool about 30 minutes.
To assemble, place one cake layer upside down on a cake platter. Spread with the custard. Place the other cake layer on top, right side up. Spoon the ganache over the top, allowing it to drip down the sides of the cake. Refrigerate until serving.