Preheat the oven to 350°F. Lightly grease a 9 x 5-inch loaf pan and line it with parchment paper, covering the bottom and the two longest sides of the pan with some overhang (for easy lift it out). Set aside until needed.
In a large bowl, coarsely mash the bananas using a fork. Whisk in the melted butter until well combined. Add the eggs, sugar, vanilla extract, and mix until thoroughly combined.
In a medium bowl, whisk together the sifted flour, baking soda, cinnamon, and salt to combine. Add the flour mixture to the banana mixture and stir to combine using a rubber spatula. Scrape the sides and base of the bowl well to ensure the mixture is uniformly combined. Gently fold in the chocolate chips and walnuts, mixing just until combined.
Pour the batter into the prepared loaf pan and even it out. Then press the remaining halved banana into the top of the bread, cut side up and sprinkle with the reserved chocolate chips.
Bake in the center of the oven for 55 to 60 minutes or until a skewer inserted into the center of the cake comes out clean.
Remove the banana bread from the oven and place on a wire rack to cool for 10 to 15 minutes. Then, remove the bread from the pan and cool on the wire rack until you're ready to slice and serve. Enjoy!
Notes
Loaf pans can very in size. I used a standard metal 9x5" pan. If yours is smaller or larger or made of glass, the baking time will vary. How to store banana bread:
Store any uneaten banana bread in an airtight container at room temperature for about 3 days.