Sift together flour, baking powder, sugar and salt. Beat egg whites until stiff but not dry. Set aside. Beat egg yolks until thick and lemon colored. Continue beating adding milk and oil. Add dry ingredients and beat until smooth. Fold in beaten egg whites. Pour 1 cup batter on preheated grid. Close unit and bake until light goes out (about 5 minutes). Makes 8 large waffles.