Preheat your oven to 350°F (175°C). Grease or line a 9×5-inch loaf pan with parchment paper.

In a large mixing bowl, mash the bananas until smooth. Stir in the melted butter, then add the brown sugar, eggs, and vanilla extract. Mix well.

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

Gradually add the dry ingredients to the wet ingredients, folding gently until just combined.

Fold in the chocolate chips and optional walnuts, ensuring even distribution.

Pour the batter into the prepared loaf pan and smooth the top. Optionally, sprinkle extra chocolate chips on top.

Bake for 50–60 minutes. When done, a toothpick inserted in the center should come out clean or with a few moist crumbs.

Remove from oven, cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.