Preheat oven to 350°. Bake oats in a single layer in a shallow pan 10 minutes or until lightly toasted, stirring after 5 minutes. Let cool on a wire rack 10 minutes. Process oats in a blender or food processor 30 seconds or until finely ground.
Sift together flour, baking powder, and salt in a large bowl; stir in ground oats.
Beat egg whites at high speed with an electric mixer until soft peaks form.
Whisk together egg yolks, milk, butter, and honey in a medium bowl; gently stir into oat mixture. Gently fold in egg whites just until blended.
Cook batter in a preheated, oiled waffle iron until golden. Serve each waffle with 1 tsp. butter and 1 Tbsp. maple syrup, if desired.
Note: Nutritional analysis totals include 1 tsp. butter and 1 Tbsp. maple syrup.