5 egg yolks
1 1/2 c. sugar
1 1/4 c. pastry flour, sifted
1 tsp. vanilla
1/2 tsp. grated lemon rind
5 egg whites

Place egg yolks and sugar in mixing bowl and beat until lemon colored. Add flour, blending in well. Add vanilla and lemon rind. Beat egg whites until stiff but not dry and fold into cake mixture. Butter and flour cake pan about 18" square. Pour in cake batter and bake in moderate oven, 375 degrees, for 40 minutes. Turn over on cake rack and cool.