01 - Preheat oven to 350°F. Grease a 9x5-inch loaf pan and line with parchment paper for easy removal.
02 - Whisk together flour, baking soda, salt, and cinnamon in a large bowl until well blended.
03 - Whisk melted butter, granulated sugar, and brown sugar in another large bowl until smooth and combined.
04 - Beat in eggs one at a time, then mix in vanilla extract, mashed bananas, and sour cream or Greek yogurt until fully incorporated.
05 - Gently fold dry ingredients into wet ingredients using a spatula until just combined. Avoid overmixing to prevent tough texture.
06 - Fold in chocolate chips and nuts, reserving a few chocolate chips for topping if desired.
07 - Pour batter into prepared loaf pan and sprinkle reserved chocolate chips on top.
08 - Bake for 50-60 minutes until a toothpick inserted into the center comes out with just a few moist crumbs.
09 - Cool in pan for 10 minutes, then transfer to wire rack to cool completely before slicing.