Heat waffle iron. Preheat oven to 200 degrees F.
Combine flour, arrowroot, baking powder, salt, and sugar using.
Beat the egg yolk, milk, vanilla and butter together.
Combine wet ingredients to dry ingredients. Whisk until incorporated.
Whisk the egg white until soft peaks form using an electric mixer.
Carefully fold the egg whites into batter.
Cook waffles according to your waffle maker.
Place waffles directly on the oven racks until ready to serve.