Place all ingredients into a blender (I use my Blendtec), except egg whites and blend until smooth. Beat egg whites in a stand mixer until stiff peaks start to form. Gently fold egg whites into blended mixture until just combined. Preheat waffle iron. Let batter sit for 5-10 minutes, then pour about a cup of batter into a greased waffle iron and cook until set. I used a belgium waffle maker for this recipe, but a regular waffle iron will work fine, too. Just adjust the amount of the batter to the size of your waffle iron plates.