Step 1

Preheat oven to 350°F and grease a 9x13-inch baking dish with butter or nonstick spray.

Step 2

In a medium bowl, whisk together the flour, baking powder, salt, and cinnamon.

Step 3

In a separate larger bowl, mash the bananas, then stir in butter, sugar, eggs, and vanilla until well combined.

Step 4

Alternate adding flour mixture and milk to the banana mixture, stirring in between additions until combined. Set aside.

Step 5

For the crumb topping:

Step 6

Combine cubed butter, brown sugar, and flour in a large bowl and mix with a fork or pastry cutter until mixture resembles coarse crumbs.

Step 7

Pour half of the batter into the prepared baking dish. Top with 1/3 of the crumb mixture, followed by remaining half of the batter. Top with remaining crumb topping.

Step 8

Bake until a toothpick inserted into the center comes out clean, 50-55 minutes.

Step 9

Serve warm or at room temperature and enjoy!