In a medium bowl, combine the flour, cornstarch, baking powder, baking soda, and salt; mix well. Add the milk, vegetable oil, egg, sugar and vanilla and mix well. Let the batter sit for 30 minutes.

Preheat a waffle iron. Do not use non-stick spray on the waffle iron; the oil in the batter will allow the waffle to release easily. Follow the directions on your waffle iron to cook the waffles.

Serve immediately with butter and syrup.