GENOISE

1/2 cup sugar
4 eggs
1/2 cup flour, all purpose
2 tablespoons corn starch
3 tablespoons butter, melted
1 teaspoon vanilla

Preheat oven to 375 degrees.
Cover the bottom of a 9 inch round pan with parchment paper. Grease and flour the bottom and sides of pan. In a large bowl, combine sugar and eggs.
Whip over double boiler on top of stove until mixture is foamy and hot. Continue beating with an electric mixer off the stove until mixture quadruples in volume. Sift flour. Melt butter. Fold flour in egg mixture alternating with butter. Fold in vanilla. Spread cake mixture over the bottom of pan.
Bake 12 minutes. Unmold cake over a wire rack. Cool. Use as needed for various cakes.
CHOCOLATE GENOISE:
Substitute 1/2 cup flour with 1/4 cup flour and 1/4 cup cocoa.

Also see: COCOA SPONGE CAKE