Step 1

Move oven rack to lowest position. Heat oven to 375°F.

Step 2

Mix powdered sugar and flour; set aside. Beat egg whites and cream of tartar in large bowl with electric mixer on medium speed until foamy. Beat in granulated sugar, 2 tablespoons at a time, on high speed, adding vanilla, almond extract and salt with the last addition of sugar. Continue beating until stiff and glossy meringue forms. Do not underbeat.

Step 3

Sprinkle sugar-flour mixture, 1/4 cup at a time, over meringue, folding in just until sugar-flour mixture disappears. Push batter into ungreased angel food cake pan (tube pan), 10x4 inches. Cut gently through batter with metal spatula.

Step 4

Bake 30 to 35 minutes or until cracks feel dry and top springs back when touched lightly. Immediately turn pan upside down onto heatproof funnel or bottle. Let hang about 2 hours or until cake is completely cool. Loosen side of cake with knife or long, metal spatula; remove from pan.