Preheat your oven to 350°F (175°C) and prepare a 9×5-inch loaf pan by greasing it or lining it with parchment paper.

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

In a separate bowl, whisk together the flour, baking soda, salt, and cinnamon if using.

Gradually add the dry mixture into the banana mixture, stirring gently until just combined.

Fold in the chocolate chips and walnuts if desired.

Pour the batter into the prepared loaf pan, smoothing the top with a spatula.

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

Allow the banana bread to cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.