Preheat your oven to 350°F (175°C) and grease a standard loaf pan with butter or non-stick spray.

In a large mixing bowl, mash the overripe bananas until completely smooth.

Pour in the melted butter and whisk in the eggs and brown sugar until well combined.

In a separate bowl, whisk together the all-purpose flour, baking powder, cinnamon, and salt until evenly incorporated.

Gradually fold the dry ingredients into the wet mixture using a spatula.

Spread half of your batter evenly into the prepared loaf pan. Sprinkle half of the cinnamon-sugar mixture on top, then repeat with the remaining batter and cinnamon sugar.

Using a knife or skewer, gently swirl through the batter to create distinct cinnamon pockets.

Bake for 60-70 minutes until the top is golden brown and a toothpick inserted comes out clean.

Remove from the oven and let it cool in the pan for 10-15 minutes before transferring to a wire rack.