Makes 1 (10-inch) cake or 3 (8- or 9-inch) layers
4 eggs, separated
2/3 cup cold water
1 cup sugar
1-1/2 cups cake flour
1/4 teaspoon salt
1 teaspoon lemon extract
1 teaspoon cream of tartar
Preheat oven to 325F (165C).
In a large bowl, combine egg yolks and water. Beat at high speed 5 minutes or by hand until mixture is very fluffy and pale yellow. Gradually add sugar and beat 4 minutes longer at high speed or by hand until mixture is very light and fluffy.
Sift flour and salt together into a medium-sized bowl. Add to egg-yolk mixture with mixer at low speed. Blend in lemon extract. In another large bowl with clean mixer
blades, beat egg whites until frothy.
Add cream of tartar; beat until whites are stiff but not dry. Using a spatula, gently fold egg whites into egg-yolk mixture. Turn batter into an ungreased 10-inch tube pan or 3 round, 8- or 9-inch, cake pans.
Bake 60 to 65 minutes for a tube pan or 25 to 30 minutes for layer pans or until golden and top springs back when lightly touched. Immediately invert tube pan over a funnel or bottle; let hang until completely cool.
Cool layer cakes in pans on racks. Remove cooled cakes from pans.