Sift together the dry ingredients (flour, cornstarch, sugar, baking soda, salt) into a large mixing bowl.
Whisk in the wet ingredients (milk substitute, lemon juice or vinegar, oil, vanilla extract, and egg).
When your Belgian waffle iron is ready, spray with cooking spray, and pour batter into the hot waffle iron according to manufacturer's instructions (in our waffle iron, that's about a cup of batter). Cook until golden brown and crispy. Hopefully you listened to us and bought a waffle iron with a ready light, so you'll know exactly when that is.