Preheat the oven to 375F degrees. Spray a 2-quart (or 9x9-inch) baking dish with nonstick cooking spray.
Make the streusel: In a bowl, using a fork, stir together the brown sugar, flour and butter, until crumbly. Then stir in the oats and pecans. Set aside.
Make the filling: In a medium bowl, whisk together the flour, sugar and milk just until blended. Whisk in melted butter. Then pour into the prepared baking dish.
Layer banana slices on top.
Then crumble streusel topping evenly on top of the banana layer.
Bake for about 45-50 minutes until golden brown and no longer jiggly.
Dig in! Optional: Serve with a scoop of vanilla ice cream and slices of banana.
Video
Notes
This original recipe was made with a banana milk product that is no longer produced. So I have updated the recipe to just use regular milk. Also, I have made this with a banana protein drink and it turned out great as well. You could also add about a teaspoon of banana extract to the milk to get a stronger banana flavor.
Make sure your bananas are ripe. They should have brown spots on them. This will produce the best flavor.