11egg whites from large eggsthe closer to room temperature the better
1/3cwarm water
1teaspoonvanilla extract
1 ½ teaspoonscream of tartar
1/4cupunsweetened cocoa powder
Instructions
Preheat oven to 350 F.
In a food processor spin sugar about 2 minutes until it is superfine.
Sift half of the sugar with the salt the cake flour, setting the remaining sugar aside.
In the bowl of a stand mixer fitted with the whisk attachment, whisk together the egg whites, water, vanilla, and cream of tartar for about 1 minute on low.
Slowly sift the reserved sugar in, beating continuously at medium-high speed.
Once the eggs are thick and glossy and hold their peaks when you lift the whisk out, sift enough of the flour mixture in to dust the top.
Using a spatula fold in gently.
Continue until all of the flour mixture is incorporated.
Remove about half of the mixture to a separate bowl.
Sift half cocoa powder over that half of the batter.
Gently fold cocoa powder in.
Repeat with remaining half cocoa powder.
Alternate regular and cocoa batters in ungreased tube pan.
Bake for 30 minutes before checking for doneness with a wooden skewer. (When inserted halfway between the inner and outer wall, the skewer should come out dry).
Cool upside down on cooling rack for at least an hour before removing from pan.