2tablespoonswater, or 1 tablespoon each water and lemon juice
1teaspooncream of tartar
Preheat the oven to 350°F.
Sift the sugar twice. Sift the flour, salt and 1/2 cup of sugar together 3 times. (This will ensure that the flour and sugar have absolutely no lumps and that they are all well mixed together.)
Whip the egg whites and water until foamy. Add the cream of tartar to the egg whites and continue to whip until they are stiff, but not dry. Whip in 1 tablespoon of the remaining sugar at a time. Fold in the vanilla and almond extract. Sift 1/4 cup of the flour and sugar mixture over the batter. Fold it in gently and briefly with a rubber spatula. Continue until all the flour mixture is used.
Pour the batter into an ungreased tube pan. Bake about 45 minutes in the preheated 350°F oven. Invert the pan and rest it on an inverted funnel or some other object that allows it to remain upside down. Let the cake hang for 90 minutes before removing it from the pan.