In a large bowl, whisk together the flour, cornstarch, salt, baking soda, and baking powder. In a separate bowl, mix the egg, sugar, butter, shortening, and vanilla until smooth.
Gradually incorporate the milk, half-and-half, and buttermilk. Fold the wet ingredients into the dry ingredients until just combined, leaving a few lumps.
Preheat your waffle iron and coat it with cooking spray.
Pour about 1/2 cup of the batter into the iron and cook until the waffles are golden and crispy, roughly 4 to 6 minutes.