Orange juice and oatmeal add an unusual twist to an old breakfast favorite. The waffles are light and tender due to the addition of beaten egg whites and buttermilk. This batter doesn't hold well because the egg whites lose their volume over time, but it will hold overnight in the refrigerator without any loss in taste. For best result, serve the waffles hot with whipped butter and warm maple syrup.
Preheat your waffle iron.
Place the melted butter, egg yolks, buttermilk, and orange rind in a small bowl and whisk to blend.
Place the oats in the bowl of a food processor and grind to a powder.
In a large bowl, whisk together the oat powder, flour, baking soda, baking powder, salt, and nutmeg. Pour the buttermilk mixture into the dry ingredients and stir just until combined. Do not overmix.
Place the 4 egg whites in a clean bowl and beat with an electric mixer on medium until foamy. Add the sugar gradually, beating on high until the whites are stiff but not dry. Lighten the waffle batter with about one-third of the beaten egg whites, then carefully fold in the remainder of the whites.
Cook the waffles according to the manufacturer's directions. Serve hot.