Cheap Sponge Cake
Yolks 3 eggs
1 cup sugar
1 tablespoon hot water
1 cup flour
1½ teaspoons baking powder
¼ teaspoon salt
Whites 3 eggs
2 teaspoons vinegar
Beat yolks of eggs until thick and lemon-colored, add sugar gradually, and continue beating; then add water, flour mixed and sifted with baking powder and salt, whites of eggs beaten until stiff, and vinegar. Bake thirty-five minutes in a moderate oven, in a buttered and floured cake pan.