In a large bowl, beat together the egg yolks, buttermilk and butter or oil till well combined. In a separate bowl, sift together dry ingredients. Gently stir dry ingredients into wet ingredients.
Beat egg whites till stiff. Gently fold them into batter.
Bake waffles in a preheated, oiled waffle iron till done.
Charles notes that adding an additional tablespoon of buttermilk to the batter will make extra-crisp waffles.