In a bowl, combine the flour, sugar, baking powder and salt.

In another bowl, combine the egg yolks, milk and oil; stir into dry ingredients just until moistened.

In a small bowl, beat egg whites until stiff peaks form, Add to waffle batter and gently fold into batter. Bake in a preheated waffle iron according to manufacturer's directions. This made 9 waffles for me using 1/2 cup batter for each waffle.