Preheat waffle iron.

Sift then measure flour. Add baking powder, salt, and sugar in large bowl.

Combine egg yolks, milk, & cooking oil in a small bowl. Add to dry ingredients. Mix until well blended.

Fold stiffly beaten egg whites into the batter with a spatula.

Pour batter into center on hot waffle iron. Bake until steaming stops.

Lift off carefully with spatula. Serve immediately.