Preheat oven to 375. In a mixing bowl, combine powdered sugar and flour; set aside. In another mixing bowl, with mixer at high speed, beat egg whites, cream of tartar, vanilla extract, salt, and almond extract until well blended. Beating at high speed, gradually sprinkle in granulated sugar, 2 tablespoons at a time. Beat just until sugar is dissolved and egg whites stand in stiff peaks. Do not scrape sides of bowl during beating. With rubber spatula, fold in flour mixture, about 1/4 at a time, just until flour disappears. Pour mixture in unprepared 10" tube pan. With metal spatula, cut through batter to break large air bubbles. Bake for 35 minutes. Remove from oven and set upside-down until cooled.