Adjust the oven rack to the lower middle position and preheat oven to 325°F.
Put some foil around the outside of the tube pan to prevent oven mishaps.
Stir the cake flour, 3/4 cup of the superfine sugar, and salt in a bowl.
In a stand mixer fitted with a whisk attachment, whip egg whites and cream of tartar together until foamy. Switch to high and pour in the remaining 1 cup of the superfine sugar.
Whip until soft peaks form, about 4-6 minutes.
Add the vanilla and almond extract, and blend in.
Use a small mesh strainer to sprinkle in the flour mixture about half cup at a time, then gently folding each in before adding more.
Spread batter into an ungreased 9 inch tube pan. Tap the pan lightly on the counter to smooth down the surface.
Bake the cake until a toothpick inserted comes out clean, about 45-50 minutes. Rotate the pan halfway through baking.
Cool cake completely while resting with the pan upside down, several hours.
Run a thin knife around the edges to release the cake, then again on the bottom of the pan once it comes out of the top part of the pan. You may need to run the knife underneath to release the tube if it sticks.