1 1/4 cups rice flour 1 1/4 cups potato flour 2 1/2 cups sugar 15 eggs

2 1/2 teaspoons salt 1/4 cup lemon juice or 2 1/2 teaspoons extract 2 1/2 teaspoons cream tartar

Beat yolks until thick and lemon colored; add sugar gradually, beating all the time; add lemon. Beat whites until foamy, add cream of tartar, and beat until stiff and dry. Sift flour and salt together, and fold into yolks alternately with whites. Bake as any sponge cake.