Sift salt and baking powder with the flour; rub in the butter. Mix and add the beaten yolks and milk, and last stir in the whites which have been beaten to a stiff froth. Bake at once in well-greased waffle-irons. By using two cups of milk, the mixture is right for pancakes. If sour milk is used, substitute soda for the baking powder. Sour cream makes delicious waffles.
The Easiest Way in Housekeeping and Cooking (1903).