Assemble your ingredients.

Preheat the oven to 350°F.

Lightly grease a 9-inch loaf pan. Line this with parchment paper, pushing the paper into the pan so the grease holds it in place.

In a large mixing bowl, mash the bananas. Stir in the melted butter. Then, add the beaten egg and stir to combine well. Add the flour, sugar, baking soda, salt, and cinnamon. Stir to combine into a smooth batter.

Fold in the walnuts pieces and chocolate chips if using.

Pour the batter into the loaf pan and even it out with an offset or silicone spatula.

Place the pan in the oven and bake until a toothpick inserted into the center comes out clean, approximately 55 minutes.

Remove the bread pan to a cool stove burner and allow it to rest for 30 minutes.

Remove the bread from the pan and place it on a wire rack to continue to cool and set for another 20 minutes. Once cool, slice and serve.