Using a whisk, mix together the flour and cornstarch in a bowl. Add sourdough discard, milk, buttermilk, vegetable oil, sugar and eggs. Whisk together until fully combined
At this point you can refrigerate the batter overnight for about 12-24 hours or you can continue with the recipe and make the waffles right away. Refrigerating the batter will give the waffles more flavor but both options are delicious.
Pull the batter out of the fridge, if refrigerated, and continue adding ingredients: baking soda, baking powder, salt and vanilla. Stir until fully incorporated.
Heat waffle irons and put about ⅓ - ½ cup of waffle batter onto hot iron. Bake according to the directions on your waffle iron. Ours usually take 2-3 minutes per waffle.
Serve immediately with hot syrup, berries or even powdered sugar and whipped cream. Eat immediately. Waffles can be re-toasted in the toaster to bring back a little bit of the crispiness if you want to freeze the extras for a later time. Enjoy!