Preheat your waffle iron according to manufacturer instructions. For crispier waffles, use a higher heat setting if available.
In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt.
In a medium bowl, whisk together the milk, melted butter, eggs, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir just until combined. The batter should be slightly lumpy—do not over-mix.
Lightly grease the hot waffle iron with butter, oil, or nonstick spray. Add about 1/3 cup of batter per waffle (adjust for your iron). Close and cook until golden brown and crisp.
Transfer cooked waffles to a wire rack to keep them crisp. Serve hot with maple syrup, butter, or your favorite toppings.