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

In a large mixing bowl, mash the three ripe bananas until smooth. Stir in the melted unsalted butter, then add the brown sugar, eggs, and vanilla extract, mixing until fully combined.

In a separate bowl, whisk together the all-purpose flour, baking soda, salt, and cinnamon (if using).

Gradually add the dry ingredient mixture to the banana mixture, stirring gently until there are no visible streaks of flour.

Gently fold in the chocolate chips and walnuts (if using) into the batter.

Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Bake for 50 to 60 minutes, checking for doneness with a toothpick.

Let the banana bread cool in the pan for about 10 minutes before transferring to a wire rack.