SPONGE CAKE

Beat egg yolks with wire whip until thick; add gradually sugar which has been sifted, then grated lemon rind, lemon juice and ½ beaten whites; mix well; carefully fold in flour which has been sifted with baking powder and salt; mix in remainder of egg whites. Bake in ungreased tube pan in moderate oven 35 to 45 minutes. When cake shrinks from pan remove from oven and turn upside down on cake cooler. It will gradually come out of pan.