Sift flour and 1/2 cup sugar together four times; set aside. In a bowl, combine egg whites, cream of tartar, extracts and salt; beat on high until soft peaks form but mixture is still moist and glossy. Add remaining sugar, 1/4 cup at a time, beating well after each addition. Sift flour mixture, a fourth at a time, over the egg white mixture; fold in gently, using about 15 strokes for each addition. Spoon batter into an ungreased 10-in. tube pan (pan will be very full). Bake at 375° for 35-40 minutes or until top crust is golden brown and cracks feel dry. Immediately invert cake in pan to cool completely. Loosen sides of cake from pan and remove.