Preheat waffle iron according to manufacturer's instructions. In a large bowl, add flour, sugar, baking powder, and salt. Whisk together until combined. Set aside.
In a medium bowl, add egg yolks, milk, melted butter, and vanilla extract. Whisk together to combine. Add to dry ingredients and whisk together just until combined.
Beat egg whites until soft peaks form. Add to batter and gently fold in just until combined.
Spray nonstick spray on preheat waffle iron. Add batter to waffle iron and cook according to manufacturer's instructions. Mine held 1 cup of batter but yours could hold more or less depending on the size of the iron. Repeat with all of the batter.
Serve with sliced strawberries. powdered sugar, and maple syrup.