In a large bowl, stir together flour, brown sugar, baking powder, cinnamon, and salt. Stir in oats. Make a well in the center of flour mixture; set aside.
In a medium bowl beat eggs slightly. Stir in milk and oil. Add egg mixture all at once to flour mixture; stir until combined.
Pour a generous cup of batter onto grid of a preheated, lightly greased waffle maker. Close lid quickly, do not open during baking. Bake according to manufacturer's directions. Use a fork to lift baked waffle off grid.
Repeat with remaining batter. If desired, sprinkle waffles with powdered sugar, serve with maple syrup, or top with fruit and yogurt.