In a large bowl, whisk together the flour, sugar, baking powder, cinnamon, and salt.
In a medium bowl, whip the egg whites on medium-high speed until stiff peaks form; set aside.
In another medium bowl, whisk together the egg yolks, melted butter, milk, and vanilla extract.
Add the wet ingredients to the flour mixture and whisk gently to combine. Add one-third of the egg whites and stir gently with a rubber spatula. Add the remaining egg whites and fold gently with a rubber spatula until no white streaks remain.
Cook according to the waffle maker’s instructions. Serve with your favorite waffle toppings; popular options are butter and syrup, fresh fruit, whipped cream, and a dusting of powdered sugar.