
Preheat waffle iron according to manufacturer instructions and lightly grease if needed.
In a large bowl, whisk together oat flour, baking powder, baking soda, salt, and sugar.
Add eggs, milk, melted butter, and vanilla, and whisk until smooth and just combined.
Let batter rest for 10 minutes to thicken slightly. The batter should look like thick, smooth heavy cream. If it’s too thin, add 1-2 tbsp more flour. If it’s too thick, add 1-2 tbsp more milk.
Scoop ¼ cup of batter into the waffle iron and cook according to your machine, about 3–5 minutes, until golden and crisp.
Remove waffles carefully and repeat with the remaining batter. Serve warm.