Preheat the waffle iron. Set it to medium-high heat. If it has a temperature dial, aim for a setting that produces a deep golden brown without scorching.

Make oat flour. Blitz 1 cup rolled oats in a blender until fine and sandy. You should end up with about 1 cup of oat flour. Measure after blending for accuracy.

Combine dry ingredients. In a large bowl, whisk 1 cup oat flour, 1/2 cup white whole wheat flour, 1/3 cup whey protein powder, 2 tablespoons cornstarch, 2 teaspoons baking powder, 1/4 teaspoon baking soda, 1/2 teaspoon salt, and 1/2 teaspoon cinnamon.

Whisk wet ingredients. In a separate bowl, whisk 3/4 cup Greek yogurt, 3/4 cup milk, 2 eggs, 2 tablespoons neutral oil, 1–2 tablespoons maple syrup, and 1 teaspoon vanilla until smooth.

Bring the batter together. Pour wet into dry and whisk just until combined. The batter should be thick but pourable; add a splash of milk if it feels too stiff. Let it rest 5 minutes to hydrate the oats and activate leavening.

Prep the iron. Lightly grease the waffle plates with cooking spray or a thin swipe of butter. Don’t overdo it—too much fat can make waffles soggy.

Cook. Add enough batter to cover the iron (usually 1/3 to 1/2 cup per standard waffle). Close and cook until steam mostly subsides and the exterior is deep golden and crisp, 3–5 minutes depending on your machine.

Hold for crispness. Transfer finished waffles to a wire rack set over a sheet pan. Keep them in a 200°F (95°C) oven while you finish the batch so they stay crisp.

Serve. Top with a pat of butter, a drizzle of warm maple syrup, fresh berries, or a dollop of yogurt. For extra protein, add peanut butter or a spoon of cottage cheese.