01 - Preheat the oven to 350°F. Grease and flour a 9x5-inch loaf pan or line it with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking soda, salt, and cinnamon if using.
03 - In a separate bowl, blend mashed bananas, melted butter, milk, eggs, and vanilla extract until smooth.
04 - Gently fold the wet ingredients into the dry mixture until just combined to avoid overmixing.
05 - Fold in semisweet chocolate chips and chopped walnuts evenly into the batter.
06 - Pour batter into the prepared loaf pan and smooth the surface.
07 - Bake for 50 to 60 minutes until a toothpick inserted in the center comes out clean or with a few moist crumbs.
08 - Allow to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.