Preheat your oven to 350°F (175°C) and prepare a 9x5-inch loaf pan with parchment paper.

Melt ½ cup of unsalted butter over medium heat for 5-7 minutes until golden brown and nutty in aroma.

Mash 3 ripe bananas until smooth, then add ¾ cup of granulated sugar and mix until combined.

Pour the browned butter and add 2 large eggs into the banana mixture, mixing until blended.

Whisk together 1 ½ cups of flour, 1 teaspoon of baking soda, ½ teaspoon of baking powder, ½ teaspoon of salt, and 1 teaspoon of cinnamon in a separate bowl.

Fold the dry mixture into the wet ingredients gently to avoid overmixing.

For the streusel, mix ½ cup of chopped walnuts, ¼ cup of brown sugar, ¼ cup of flour, and 2 tablespoons of cold butter until crumbly.

Pour the banana batter into the prepared pan and sprinkle the walnut streusel evenly on top.

Bake for 60-75 minutes until a toothpick comes out clean from the center.

Allow to cool in the pan for 15 minutes then transfer to a wire rack to cool completely before slicing.

Slice and enjoy either warm or toasted, possibly with butter or your favorite spread.