01 - Preheat the oven to 350°F. Grease a 9x5-inch loaf pan and line with parchment paper for easy removal.
02 - In a large bowl, whisk together the flour, baking soda, salt, and cinnamon until evenly distributed.
03 - In another large bowl, whisk together the melted butter, granulated sugar, and brown sugar until smooth. Beat in the eggs one at a time, then mix in the vanilla extract, mashed bananas, and sour cream or Greek yogurt until well combined.
04 - Add the dry ingredients to the wet ingredients and gently fold together with a spatula until just combined. Do not overmix.
05 - Fold in the chocolate chips and nuts, reserving a few chocolate chips for topping if desired.
06 - Pour the batter into the prepared loaf pan. Sprinkle reserved chocolate chips on top. Bake for 50-60 minutes, or until a toothpick inserted into the center comes out with just a few moist crumbs.
07 - Cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.