- Preheat waffle iron.
- Combine dry ingredients in large bowl and whisk together.
- In a large measuring cup (4-cup Pyrex) or medium bowl combine buttermilk, milk, egg yolks, butter, vanilla and orange zest, if using.
- Whip the egg whites with hand mixer in medium bowl until soft peaks form.
- Pour buttermilk mixture into flour mixture, gently combine until few streaks of flour remain. Do not over beat, batter will be lumpy. Gently fold in whipped egg whites.
- Cook according to your waffle maker.