Preheat the waffle iron according to the manufacturer's instructions.

In a mixing bowl, whisk together the flour, sugar, baking powder, and salt.

In another bowl, mix the milk, vegetable oil, egg, and vanilla extract until well combined.

Pour the wet ingredients into the dry ingredients and stir just until combined; a few lumps are okay.

Lightly grease the preheated waffle iron with cooking spray or oil.

Pour about 1/2 cup of batter per waffle onto the waffle iron, close the lid, and cook for 4–5 minutes or until golden brown.

Carefully remove the waffle and serve hot with your favorite toppings.

Repeat with the remaining batter, greasing the iron as needed.