Preheat waffle maker and coat with nonstick oil spray.

Add egg whites in the bowl of a stand mixer, mix until stiff peaks form

Whisk flour, baking powder, sugar, salt, and cinnamon together in a large mixing bowl. In a separate bowl,whisk together buttermilk, vegetable oil, egg yolks, and vanilla. 

Whisk wet ingredients into the dry ingredients, then gently fold in egg whites. Pour about ½ cup batter into each waffle mold, and then cook according to waffle maker directions. (NOTE: THIS MINI HEART WAFFLE MAKER USES LESS THAN ¼ CUP OF BATTER)

Serve waffles immediately.