Start by beating the egg whites with a pinch of salt until they're frothy. Then, add cream of tartar and continue beating until the whites are stiff, but not dry.
Sift the flour and sugar 4 times each, separately. Gradually add the sugar to the egg whites and fold in the flour. Finish by adding vanilla extract.
Bake the angel cake for 40 minutes or until a toothpick inserted into the center comes out clean.