Step 1

Preheat the oven to 350°F. Grease a 10x5-inch loaf pan and line with parchment paper. Set aside.

Step 2

Following the instructions for how to brown butter, brown the butter in a saucepan over medium heat. When browned, remove from the heat and pour into a bowl to cool while you work on the batter.

Step 3

In a large bowl, whisk together the granulated sugar, flour, baking powder, baking soda, salt, and nutmeg.

Step 4

In a separate bowl, whisk together the mashed bananas, eggs, and vanilla extract. Pour into the dry ingredients and mix until just combined.

Step 5

Add the cooled brown butter and stir until just incorporated. Pour the batter into the prepared loaf pan.

Step 6

To make the streusel, combine the brown sugar, flour, cinnamon, and salt in a small bowl. Use a fork or your fingers to work the butter into the mixture until clumps form. Sprinkle evenly over the bread batter.

Step 7

Bake for 1 hour 10 minutes, or until a toothpick inserted into the center comes out clean. Let cool for 15 minutes in the pan, then transfer to a wire rack to cool completely.