1. Preheat your oven to 350°F (175°C). Do not grease your angel food cake pan to ensure proper rise.
2. Mix superfine sugar and sifted cake flour in a bowl; whisk until evenly combined.
3. In a clean, large bowl, beat egg whites on medium until frothy. Add cream of tartar and salt, then increase to high speed.
4. Add remaining sugar gradually, beating until stiff, glossy peaks form. Stir in vanilla and optional almond extract.
5. Gently fold in the flour mixture in three parts, using a spatula to preserve the airy texture.

Pouring and Baking

1. Pour the batter into an ungreased angel food cake pan. Smooth the surface with a spatula.
2. Bake for 35-40 minutes until golden brown and a toothpick inserted into the center comes out clean.
3. Invert the pan onto a bottle or cooling rack and cool completely upside down.
4. Run a knife around the edges and center tube before removing from the pan.