Sift flour with first sugar four times; set aside. Beat egg whites with salt until foamy, then add cream of tartar and beat until stiff. Add remaining sugar one tablespoon at a time, folding into egg whites. Add vanilla. Sift flour and sugar mixture over top of egg whites a little at a time and fold in. Bake in an ungreased 10-inch angel food cake pan at 325 degrees for 65-75 minutes. Invert pan to cool. Serves 12