Preheat your waffle iron and spray with non-stick cooking spray.
In a large bowl, whisk together the flour, cinnamon, salt, baking soda, baking powder, and sugar. Make sure there aren't any clumps.
Separate the egg whites into a small bowl and set aside. In a medium bowl, whisk the milk, melted butter, egg yolks, and vanilla until smooth.
Add the wet ingredients to the dry ingredients and whisk until smooth.
Using a hand-held or stand mixer, beat the egg whites until stiff peaks form. This will take about 5 minutes.
Fold the egg whites into the batter until combined.
Cook in the preheated waffle iron, spray again with non-stick spray between each.