Preheat your waffle iron (use a higher heat setting for extra crispy waffles).
In a large bowl, whisk together the flour, sugar, baking powder, and salt.
In a medium bowl, combine the milk, melted butter, eggs, and vanilla, whisking until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined.
Grease the preheated waffle iron with cooking spray or butter.
Add about 1/3 cup of batter to the iron (adjust based on your waffle maker size).
Cook until golden brown, then place on a wire rack to maintain crispness.
Serve warm with maple syrup, butter, or any preferred toppings.