Below is a great recipe for sponge cake!
1 1/4 c sugar
1 c potato starch
Juice of one orange
Juice of one lemon
Using 2 large mixing bowls, separate 7 of the 9 eggs. Add the remaining 2 whole eggs to the bowl with the yolks and beat until foamy. Gradually add the sugar; beat until light and lemon-colored. Add the potato starch alternately with the juices. With an electric mixer, beat the egg whites until stiff and dry. Carefully fold the yolk mixture into the stiffly beaten egg whites. Pour into an ungreased 10-inch tube pan. Preheat oven to 325 degrees and bake for 1 hour and 10 minutes. Invert and cool for at least 1 hour. Serves 10 or more.
Banana-Nut Cake: Omit the orange juice. Increase the lemon juice to the juice of two lemons. Add 2 ripe bananas, mashed, along with 1/2 c chopped nuts.