Preheat your waffle iron, according to manufacturer's instructions, to medium-high and spray with nonstick cooking spray.
In a small skillet, heat butter over medium heat whisking constantly. Cook until butter is melted and begins to brown. Remove from heat and let cool to room temperature.
In a large bowl, whisk together both flours, brown sugar, baking powder, salt, and cinnamon.
Whisk in cooled butter, eggs, milk, and vanilla until just combined. Gently fold in mashed bananas.
Scoop waffle batter by about 1/2 cupfuls onto preheated waffle iron. Cook, according to manufacturers instructions, until waffle is golden brown on both sides; about 5-6 minutes. Repeat with all remaining batter spraying with cooking spray in between batches so waffles do not stick.
Serve immediately, topped with extra bananas and fresh maple syrup.
Notes
To keep waffles crispy in between cooking, place on wire baking rack to cool.Adapted from Two Peas & Their Pod