To Mix Sponge Cake

Separate yolks from whites of eggs. Beat yolks until thick and lemon colored, using an egg beater; add sugar gradually, and continue beating; then add flavoring. Beat whites until stiff and dry, — when they will fly from the beater, — and add to the first mixture. Mix and sift flour with salt, and cut and fold in at the last. If mixture is beaten after the addition of flour, much of the work already done of enclosing a large amount of air will be undone by breaking air bubbles. These rules apply to a mixture where baking powder is not employed.