Preheat Oven: Preheat oven to 350°F (175°C). Grease or line a 9×5-inch loaf pan.
Mash Bananas: In a large bowl, mash ripe bananas until smooth.
Brown the Butter (optional): Melt butter over medium heat until golden and fragrant. Let cool slightly.
Mix Wet Ingredients: Combine mashed bananas, brown butter, sugar, eggs, and vanilla extract. Whisk until smooth.
Add Dry Ingredients: In a separate bowl, whisk together flour, baking soda, salt, and cinnamon. Add to wet mixture and stir gently.
Add Sour Cream & Chocolate Chips: Fold in sour cream and ¾ cup chocolate chips until just combined.
Pour & Bake: Pour batter into the pan, sprinkle extra chocolate chips on top, and bake for 50–55 minutes or until a toothpick inserted in the center comes out mostly clean.
Cool & Slice: Let cool 10 minutes in the pan, then move to a rack to cool completely before slicing.