Basic Chocolate Sponge Cake

Basic Chocolate Sponge Cake
3.5 ounces dark chocolate
2 Tablespoons strong coffee
3.5 Tablespoons unsalted butter
3 eggs, separated
1/2 cup + 1 Tablespoon granulated (white) sugar
pinch salt
1 teaspoon vanilla extract
1/3 cup cake flour
Preheat oven to 300◦F. Line a nine inch springform pan with parchment paper.

In a small saucepan double-boiler, heat the chocolate, coffee, and butter until melted.
Meanwhile, beat the yolks and 1/2 cup sugar until thick, pale and yellow and forms a ribbon when the beater is trailed in. Beat in the vanilla.
Beat the egg whites and salt until soft peaks form, gradually beat in one Tablespoon sugar until stiff peaks form.

Mix the chocolate mixture into the yolks. Scoop one quarter of the whites over the yolks, then sift on one quarter of the flour and fold in. Repeat this process three times. Spread batter in prepared pan. Bake for 20 minutes until puffed, firm, and risen. Wait five minutes, then remove cake from pan and cool completely.

This is the spongecake base I used for my Charlotte Russe Malakoff au Chocolat.