Steps
- Preheat the oven to 325°F / 165°C. Set out an ungreased 10in / 25cm angel food tube pan. Mix 1 cup of cake flour with half of 1½ cups of sugar.
- Beat 1¾ cups of room-temperature egg whites, ½ teaspoon of salt, and 1 teaspoon of vanilla extract until frothy. Add 1½ teaspoons of cream of tartar and beat to stiff, glossy peaks.
- Gradually beat in the remaining sugar, then gently fold in the flour mixture. Spoon into the pan.
- Bake for 40-45 minutes, until golden and springy. Invert the pan over a bottle neck and cool for 1½ hours; loosen around the edges and center tube, then unmold.