In a bowl, mix the flour, sugar, baking powder, and salt.

Whisk the egg yolks with the milk, melted butter, and vanilla extract.

Pour the wet ingredients into the dry ingredients and mix until smooth.

In a separate bowl, beat the egg whites until stiff peaks form and gently fold them into the batter.

Preheat your waffle iron and lightly coat it with non-stick spray. Pour the batter onto the iron and cook until golden brown.

Serve with chocolate sauce, fresh fruit, or a dusting of powdered sugar.