In a large mixing bowl, sift together the flour, baking powder, baking soda, salt, and cinnamon. Set aside.
In another mixing bowl, whisk together the milk and yogurt. Stir in the egg yolks, applesauce, and oil. Whisk to combine well.
In another bowl, beat the egg whites until soft peaks form.
Pour milk mixture into the dry mixture. Stir gently to combine. Some dry bits are okay.
Fold in the egg whites until evenly dispersed.
Cook in a waffle maker according to the manufacturer's directions.
Make-ahead tips: Mix the dry ingredients together and store in a ziptop bag. Make many at one time and label with mixing instructions. Alternatively, cool baked waffles on a rack and freeze them for quick toaster breakfasts.
Nutritional values are approximate and are based on making 12 waffles from the recipe. Refrigerate leftovers promptly and use within 4 days.