For the cake: 2 cups flour 3 tsp baking powder 1 tsp salt 3 ripe bananas 1/2 cup melted butter 2 cups granulated sugar 2 eggs 3 tsp vanilla extract 1 cup sour milk ( add 1 Tbsp of vinegar to milk and let sit 5 minutes) For the streusel : 3/4 cup (12 Tbsp) melted butter 1 1/2 cups light brown sugar 1 1/2 cups flour 1 tsp cinnamon For the glaze: 1 cup powdered sugar 1 tsp vanilla extract 2 Tbsp cream

Preheat oven to 350 degrees. Grease a 9×13 baking dish with cooking spray, set aside.
In a medium bowl whisk together flour, baking powder and salt.
In another bowl, mash bananas. Mix in butter until combined and then mix in sugar, eggs, milk, and vanilla. With mixer running on low, carefully add flour and mix until just combined.
Prepare streusel by combining all the ingredients in a medium bowl, mix in the butter until a coarse crumb forms.
Pour 1/2 of the batter into the prepared pan. Top with 1/3 of the crumb mixture. Cover the filling with the remaining batter and top with remaining crumb mixture. Bake for 50-55 minutes until the center is set and a toothpick comes out clean. Cool for at least 1 hour.
Mix together the glaze ingredients and drizzle over the cake before serving.