Get prepped. Preheat the waffle iron and lightly grease it. Melt the butter and set it aside to cool slightly.
Mix the dry ingredients: In a large bowl, whisk together 1-1/2 cup all-purpose flour, 1 cup quick-cooking oatmeal, 3 teaspoons baking powder, 1 teaspoon ground cinnamon, 1 tablespoon dark brown sugar, and 1/4 teaspoon salt.
Mix the wet ingredients: In a separate bowl, whisk together 2 large eggs, 1-1/2 cup milk, 4 tablespoons butter, and 1 teaspoon vanilla extract
Combine: Add the wet ingredients to the dry ingredients and stir just until combined. The batter will be thick.
Cook the waffles: Lightly grease the waffle iron, add the batter, and cook until the waffles are golden and crisp to your liking.
Serve: Serve warm with fresh fruit, whipped cream, and maple syrup if desired.
Notes
I use quick oats in my waffles. Old fashioned rolled oats can be used, but I recommend allowing them to soak in the batter for a little bit, and adding more liquid.These waffles take a little longer to cook than regular waffles.Preheat the waffle iron well. A fully hot waffle iron helps these waffles cook evenly and crisp on the outside.Do not overmix. Stir just until combined. Overmixing leads to dense waffles.Let the batter rest. A short 5-minute rest gives the oats time to hydrate and improves texture.StorageLet the waffles cool completely, then store them in an airtight container in the refrigerator for up to 4 days.To freeze: For freezing, stack the cooled waffles with parchment paper between each one, wrap tightly in plastic wrap, and place in a freezer zip-top bag. You can also freeze the waffles in a single layer on a baking sheet until solid, then transfer them to a freezer bag or container. They keep well in the freezer for up to 2 months.To reheat: Reheat waffles straight from the fridge or freezer. Do not thaw first. Pop them directly into the toaster and heat until warmed through and crisp on the edges.Substitutions/AdditionsYou can leave out the brown sugar in these waffles, or replace them with regular sugar, honey, or even better - maple syrupYou could use oat flour (or just blast some oats in a food processor) in place of regular flour if you prefer.If you need gluten-free waffles, be sure that your oats are certified gluten-free.Almond milk, coconut milk and any other non dairy milk can be substituted if you prefer to go dairy-free.Coconut oil can be substituted for butter if you prefer.