Preheat oven to 350 degrees. Line cupcake pans with paper liners.
Place egg whites in a large mixing bowl and beat at high speed until egg whites are frothy, approximately 1 minute.
Add cream of tartar, salt and vanilla to egg whites. Mix at high speed until egg whites are almost stiff, approximately 4 minutes.
Add 1 cup of sugar gradually while mixing on low speed. Scrape bowl.
Mix flour and remaining 1/2 cup sugar together and spoon 1/4 of mixture over egg whites, folding gently between each addition.
Pour batter into cupcake liners until they are 2/3 full. Bake for 20 to 25 minutes or until tops are golden brown and cracks are very dry.
Cool cupcakes completely before removing from pan.