Preheat waffle maker to machine specifications
Place flour, baking powder, sugar, and salt in a bowl. Whisk to combine.
In a small bowl, mix egg yolks, milk, and butter. Set aside.
In a separate bowl, beat egg whites with a mixer on medium high speed until stiff peaks form.
Add egg yolk mixture to flour mixture and stir to combine.
Let mixture stand for an hour.
Fold in egg whites.
Drop by large spoonfuls onto greased waffle iron, close the lid and cook about 3-5 minutes or until steam from waffles is reduced.