In a medium saucepan, over medium-low heat, melt the butter and continue to cook until it turns a medium-brown color and has a nutty aroma, about 10 minutes. Remove from the heat, and let cool to room temperature.

In a medium bowl, whisk together flour, brown sugar, cinnamon, and salt. Add in the butter and rub it in using your fingertips until the mixture is crumbly. Stir in the pecans.

Preheat your oven to 350°F (180°C). Grease and line an 8-inch (20 cm) round cake pan and set aside.

In a small bowl, mix 1 tablespoon of sugar and ½ teaspoon of cinnamon and set aside.

In the bowl of a stand mixer fitted with the paddle attachment, mix the eggs, banana, pineapple, and vanilla on medium speed until combined, 1 to 2 minutes. Then stir in browned butter.

In a medium bowl, whisk together flour, ¾ cup (6 oz/171 g) granulated sugar, brown sugar, ½ teaspoon of cinnamon, baking powder, and salt. Gradually add your dry ingredients into your wet and mix on low until just combined.

Spread half of your batter into the prepared pan. Sprinkle with one-third of streusel and the cinnamon-sugar mixture. Top with the remaining batter, smooth the top with an offset spatula and sprinkle with remaining streusel.

Bake for 45 to 50 minutes or until a wooden skewer inserted in the center comes out clean. (If your cake is browning too fast, you can loosely cover it with foil). Let it cool in the pan for 15 minutes.

Run a sharp knife around the edges of the cake to loosen it. Invert onto a plate, then invert again onto a wire rack to cool completely.

In a small bowl, whisk together the powdered sugar, sour cream, and milk. Pour over your warm cake.

Enjoy with a cup of tea! Store any leftover cake in an airtight container at room temperature for up to 3 days.