Preheat oven to 350°F. Spray an 8.5 x 4.5-inch loaf pan with nonstick cooking spray. Set aside.

In a large bowl, mash bananas with a fork. Some chunks are okay.

To the mashed bananas, add melted butter, granulated sugar, egg, and vanilla extract. Mix well to combine.

In a separate bowl, whisk together flour, baking soda, baking powder, and kosher salt.

Gradually add the dry ingredients to the banana mixture, stirring until just combined. Do not overmix.

Pour the batter into the prepared loaf pan and smooth the top.

Bake for 45 minutes. If the top is browning too quickly, loosely cover with aluminum foil.

Continue baking for an additional 15-20 minutes, or until a toothpick inserted in the center comes out with crumbs but no wet batter.

While the bread is baking, prepare the glaze. In a medium bowl, whisk together the confectioners' sugar and milk. Add more milk until the glaze reaches your desired consistency. Set aside.

Remove the banana bread from the oven and evenly sprinkle 1-2 tablespoons of brown sugar over the top.

Turn the oven to low broil. Place the loaf back in the oven and broil for 30-60 seconds, watching carefully, until the brown sugar melts. (You can also use a kitchen torch.)

Remove from the oven. Immediately drizzle glaze over the brown sugar topping.

Let the banana bread cool in the pan for 10 minutes before serving.