Boil scant 1/2 cup water. Mix 1 tablespoon cornstarch in 1 tablespoon water and add to boiling water. Cook until clear, 1 minute; set aside. For each 9 inch pie, use 3 large egg whites, room temperature. Add pinch of salt. Beat at high speed until eggs are light and stand in peaks. Measure 9 tablespoons sugar and 2 tablespoons cornstarch mixture for each 3 egg whites. Mix with egg whites until all is used, beating constantly. Add 1/2 teaspoon vanilla. Beat 1 minute. Bake at 350 degrees for 8 to 10 minutes. Brown, but do not overbake.