6 eggs, separated and at room temperature
2 tsp lemon zest
1/4 cup fresh lemon juice
1/4 cup water
1 tsp vanilla
1 cup sugar
1-1/4 cups all-purpose flour
1/2 tsp cream of tartar
1/2 cup sugar
Preheat oven to 325
In a mixing bowl beat egg yolks on high-speed until thick; about 5 minutes. Add lemon zest, lemon juice, water and vanilla; beat on low-speed until combined. Gradually beat in 1 cup sugar at low-speed until combined. Increase speed to medium; beat until mixture thickens slightly and doubles in volume. About 5 minutes total.
Sprinkle 1/4 cup flour over egg yolk mixture; fold in until combined. Repeat with remaining flour, 1/4 cup at a time. Set mixture aside.
Thoroughly wash mixer beaters. In a large mixing bowl beat egg whites and cream tartar on medium speed until soft peaks form. Gradually add 1/2 cup sugar, beating on high-speed until stiff peaks form. Fold 1 cup of egg white mixture into the yolk mixture; fold egg yolk mixture into remaining egg white mixture. Pour batter into an ungreased 10 inch tube pan.
Bake 55 to 60 minutes or until cake springs back when lightly touched. Immediately invert cake. Let cool. Gently loosen sides of cake from pan. Remove cake.
