In your stand mixer beat the room temperature egg whites, cream of tartar, and vanilla until soft peaks form (the tips will curl with beaters lifted).
Gradually add granulated sugar, about 2 tbsps at a time, beating until stiff peaks form. This is when the meringue holds its shape and does not fall over.
In a seperate bowl, sift powdered sugar, flour, and cornstarch together. Once is great twice will five a very delicate cake.
Add 1⁄4 of the powdered sugar/flour mix to the stiff egg whites. Fold in gently. Repeat, folding in the remaining flour mix by fourths.
Pour into an ungreased 10 inch tube pan or bundt pan.
Bake on the lowest rack in a 350 degree oven for 40-45 minutes or until top springs back when lightly touched.
Immediately invert cake when you remove from oven. Cool thoroughly in pan, Loosen cake from pan, and remove.
Gluten Free
Use a gluten free flour and add 1 tsp of xanthan gum.
Notes
Chocolate Angel Food
To make Chocolate angel food cake prepare as above, except sift 1⁄4 cup unsweetened cocoa powder with the powdered sugar-flour mixture.