Preheat oven to 350 degrees F. Have ready an angel food cake pan with a removal bottom.

Put the egg whites in the bowl of a stand mixer. Add the sugar, cream of tartar and vanilla.

Using the whisk attachment, begin beating on medium. Gradually increase speed to high and beat for about 5 minutes or until mixture is thick, smooth and white. Beat in the salt.

Reduce mixer to about medium low and gradually add the instant flour, beating just until it is mixed in. Remove from stand and stir with a heavy duty scraper just to make sure all the flour is incorporated.

Scrape batter into an angel food cake pan. Smooth it evenly, then hold the pan about 2 inches off the counter and drop to release trapped air bubbles.

Bake the cake for 50 minutes. Allow it to cool for 1 hour, then remove the angel food cake from the pan by loosening around the edges and middle and bottom with a bread knife.