1 1/2 cups confectioner's sugar
1/4 teaspoon salt
1 cup cake flour, sifted
12 egg whites (1 3/4 cups) (at room temperature)
1/3 cup warm water
1 teaspoon orange extract, or extract of your choice
1 1/2 teaspoons cream of tartar
Preheat oven to 350 degrees F.
Sift half of the sugar with the salt and the cake flour, setting the remaining sugar aside.
In a large bowl, use a balloon whisk to thoroughly combine egg whites, water, orange extract, and cream of tartar.
After 2 minutes, slowly add the sifted reserved sugar, beating continuously at medium speed.
Once you have achieved medium peaks, sift enough of the flour mixture in to dust the top of the foam. Using a spatula fold in gently. Continue until all of the flour mixture is incorporated.
Carefully spoon mixture into a 10-inch (4L) ungreased tube pan. Bake for 35 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.