Preheat the oven to 350 degrees F. Spray an 8-inch square baking dish with cooking spray and lightly dust with flour.
In a medium saucepan over medium heat, melt 1/2 cup butter until it turns medium-brown in color and has a nutty aroma.
Remove from the heat and all to cool to room temperature.
In a small bowl, whisk together 1/3 cup flour, 1/4 cup brown sugar, 1/2 teaspoon cinnamon, and 1/4 teaspoon salt.
Cut in the 3 1/2 tablespoons butter until crumbly and stir in the pecans. Set aside.
Using a stand mixer with the paddle attachment, mix together the eggs, banana, pineapple, and vanilla until combined.
In a small bowl, whisk together the flour, sugar, brown sugar, salt, baking powder, and cinnamon.
Slowly add to the egg mixture and continue mixing until combined.
Sprinkle with half the streusel mixture at the bottom of the prepared baking pan.
Top with 1/2 of the cake mixture and spread evenly.
Sprinkle with the other half of the streusel mixture and top evenly with the rest of the cake mixture.
Place in the oven and bake 40 to 45 minutes, until a cake tester comes out clean. Remove from oven and all to cool in the pan on a cooling rack for 10 to 15 minutes. Run a knife along the edges and remove from the pan.
Make the glaze in a small bowl, whisk together the powdered sugar, sour cream, and milk until smooth. Drizzle evenly over the top of the cake while still warm.
*Recipe adapted from Bake from Scratch (https://www.bakefromscratch.com/browned-butter-hummingbird-coffee-cake/)