01 -
Set oven to 350°F. Coat a 9-inch square pan or 10-inch pie plate with non-stick spray.
02 -
Melt 1/2 cup butter on low heat, stirring gently until it turns golden. Let it cool, then use for the batter and crumble topping.
03 -
Combine white sugar, 1/4 cup browned butter, mashed bananas, egg, baking powder, and salt. Add milk and flour, mixing gently.
04 -
Mix packed brown sugar, cinnamon, additional 1/4 cup flour, leftover browned butter, and nuts if you like.
05 -
Spread the batter in the prepared pan, sprinkle with crumble topping, and bake 30-40 minutes, depending on the pan size.