Preheat your waffle iron to medium-high heat.
This ensures the waffles will cook evenly and have a nice crispy texture.
In a large bowl, combine the flour, cornstarch, salt, baking powder, and baking soda.
Mix them together thoroughly.
In another bowl, whisk together the egg, sugar, melted butter, and buttermilk.
Make sure the mixture is smooth.
Pour the wet ingredients into the dry ingredients.
Stir until just combined, being careful not to overmix.
Pour about 1/3 cup of the batter onto the preheated waffle iron.
Cook according to the manufacturer's instructions until golden brown and deliciously crispy.