Preheat a waffle iron according to manufacturer’s instructions. Spray the inside of the waffle iron with cooking spray.

Stir flour, milk powder, corn meal, sugar, baking powder, and salt together in a bowl. Whisk milk, eggs, butter, and vanilla extract together in a separate bowl; pour into flour mixture and stir just until batter is combined.

Pour batter, working in batches, into the preheated waffle iron and cook until golden brown, about 5 minutes.