Heat oven to 325°F/165℃.
Line the bottom of an angel food cake or tube pan with parchment paper. Set aside.
Combine flour, 1 cup sugar, and salt in a small bowl. Set aside.
Beat egg whites and cream of tartar with an electric mixer until foamy.
Stream in ½ cup sugar while beating.
Add vanilla.
Continue beating to medium peaks.
Sift flour mixture into meringue a little at a time.
Fold gently.
Spoon into prepared pan.
Tap gently to release air bubbles.
Bake for 55-60 minutes, until cake springs back when pressed.
Remove from oven.
Turn upside down on a cooling rack and allow to cool completely.
When cake is completely cool, run a thin-bladed knife around edge of pan, making sure not to cut off crust.
Turn out on rack or plate.
Peel parchment off top.