Chocolate Sponge Cake
Sift sugar, flour and cocoa together; set aside. Beat egg whites (at room temperature) at high speed of an electric mixer until foamy. Add cream of tartar and vanilla. Beat 5 minutes or until stiff peaks form. Sprinkle 1/4 of flour mixture over egg whites; gently fold in with a rubber spatula. Repeat procedure with remaining flour mixture, adding 1/4 at a time.
Spoon into an ungreased 10" tube pan with removable bottom. Bake at 375 degrees for 40 minutes or until cake springs back when touched lightly with fingers. Invert pan on funnel or bottle for 2 hours or until cake is completely cooled. Loosen cake from sides of pan, using small metal spatula; gently remove from pan.