Preheat your oven to 350°F (175°C) and grease a 9×5-inch loaf pan.

In a large bowl, combine the mashed ripe bananas, melted butter, granulated sugar, beaten egg, and vanilla extract until smooth.

In another bowl, whisk together the flour, baking soda, and salt.

Gently fold the dry ingredients into the banana mixture until just combined.

Mix brown sugar with ground cinnamon in a small bowl.

Layer half of the banana batter in the pan, sprinkle with half the cinnamon mixture, then add remaining batter and top with the rest of the cinnamon mixture.

Bake for 60-70 minutes, checking for doneness with a toothpick.

Cool the bread in the pan for 10 minutes before transferring to a wire rack.