Mix the boiling water, oil or butter, and cornmeal in a small saucepan. Cook over low-medium heat, stirring, till the mixture begins to thicken. Remove from heat. Beat the yolks and buttermilk in a large bowl. Quickly stir in the cornmeal mixture.
In one small bowl, mix the remaining dry ingredients. In another small bowl, whip the egg whites to soft peaks.
Mix the dry ingredients into the cornmeal mixture, then fold in the egg whites until incorporated. Cook in a preheated waffle iron. (One cup of batter makes a 7-inch round waffle.) Eat immediately, or cool and then freeze for future use.