In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In another bowl, whisk together the buttermilk, eggs, melted butter, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Lightly grease the waffle iron and pour the batter onto the hot waffle iron. Cook according to the manufacturer's instructions until golden brown and crisp.