Preheat oven to 350F degrees. Spray a 9×13 baking dish with nonstick cooking spray.

In a large mixing bowl, mix the flour, baking powder and salt for the batter. Set aside.

In a medium mixing bowl, add the mashed bananas and melted butter, Using a hand mixer, mix the ingredients well. Then add in the sugar, eggs, vanilla extract and milk. Mix well.

Add the liquid ingredients to the dry ingredient bowl and mix well.

In a third bowl, add the three ingredients for the crumb topping. Use a fork and cut the butter into the dry ingredients. Once the ingredients are mixed, you will have little balls forming.

In a 9x13 prepared pan, pour in half the batter. Layer half the crumb topping next and the pour the remaining batter on top. Finish with the rest of the crumb topping.

Cook for 50-60 minutes or until a toothpick comes out clean from the middle.

Allow to cool and slice. Serve warm.