Heat oven to 350 degrees F.

Using an egg separator, separate one of the eggs into a small bowl or measuring cup. Then transfer egg white to a large bowl. Repeat with remaining eggs (this keeps any yolk from accidentally getting into all your whites). Discard yolks. Let egg whites warm to room temperature. Add cream of tartar and salt to egg whites.

Beat egg whites until frothy. Gradually beat in superfine sugar, 2 tablespoons at a time, until stiff but glossy peaks form, about 5 to 7 minutes. Beat in vanilla extract.

Fold flour into egg whites in two additions, until incorporated. Spoon batter into an ungreased 10-inch tube pan.Variation for a chocolate and vanilla marbled angel food cake: Follow directions above through step 3. Then remove half of the batter to a medium-size bowl. Reduce flour to 3/4 cup. Fold 1/2 cup of the flour into the batter in one of the bowls. Sift 1/3 cup unsweetened cocoa powder and the remaining 1/4 cup flour over the second half of the batter in the other bowl and fold in both. Spoon batters alternately into a 10-inch tube pan. Swirl together with a knife for a marbled effect. Bake and cool as directed in step 5.

Bake at 350 degrees F for 35 to 40 minutes, until top has risen very high and is lightly browned and cracked. Remove from oven and immediately invert onto baking sheet or neck of bottle. Cool completely.