1 1/2 c. superfine sugar
3/4 c. + 1 1/2 tbsp. cake flour
2 c. egg whites
1 1/2 tsp. cream of tartar
1/4 tsp. salt
3 tbsp. fresh lemon juice
Zest of 2 lemons
Lemon Yogurt Glaze, optional

Sift 3/4 cup sugar 3 times. Set aside. Sift remaining 3/4 cup sugar with flour 3 times. Set aside.

Place egg whites in 4-quart greased-free bowl. Beat on low speed with mixer until frothy. Add cream of tartar and salt. Increase speed to medium and slowly add lemon juice. Beat until whites are thick and hold definite shape, but still soft and moist, about 3 minutes.

Add lemon zest, 3/4 cup sifted sugar, 1 tablespoon at a time, beating well after each addition. Increase speed to high. Continue beating until whites have increased in volume about fivefold, hold shape, are very thick, shiny and smooth, about 1 1/2 minutes more.

Gently but thoroughly fold in flour mixture, 1/3 at time. Transfer to 10 inch ungreased tube pan. Smooth surface with spatula. Cut through batter in 10 places to break any large air pockets.

Bake in center of oven at 375 degrees about 35 minutes, until surface is very brown and wood pick inserted in center comes out clean. Place sheet of foil lightly over top during last 5 minutes, if cake is too brown. Invert on empty bottle to cool.

When completely cool, use flexible knife to loosen cake from sides and then bottom of pan. Invert onto rack. Cake can be kept at room temperature as long as 2 days, well covered, or may be frozen as long as 3 months, wrapped airtight. Be sure to thaw at room temperature in wrapping.

Frost with Lemon Yogurt Glaze few hours before serving. Makes 1 (10-inch) tube cake, 12 servings.