3/4 cup egg whites (about 5 large)
1/2 cup powdered sugar
1/4 cup potato starch
1/4 cup cornstarch
1/3 cup granulated sugar
3/4 tsp cream or tartar
1/4 tsp salt
1 tsp lemon zest
Preheat oven to 375 F. Place eggs in a bowl of warm water to bring them to room temperature.
Sift together powdered sugar, potato starch, and cornstarch, set aside. Measure granulated sugar and set aside.
Combine egg whites, cream of tartar, salt and lemon peel in large mixing bowl. With mixer at high, beat until mixture forms soft peaks. Continue beating and add the granulated sugar slowly. Beat until sugar is dissolved and forms stiff peaks.
With rubber spatula, gently fold in the powdered sugar mixture about 1/4 at a time, folding just enough so the powdered sugar mixture disappears.
Pour batter into ungreased 9-inch tube pan (or two 8×4 loaf pans) and cut through with spatula to break any air bubbles.
Bake for 35 minutes or until top springs back when lightly touched. Cool in the inverted pan until completely cooled before removing from pan. Double the recipe for a 10-inch tube pan.