Preheat the oven to 350°F.
In a large mixing bowl, mash the bananas until smooth.
Add the melted butter, granulated sugar, brown sugar, egg, vanilla extract, and sour cream to the bananas. Whisk until combined.
Gradually fold the dry ingredients into the wet mixture, stirring gently until just combined. Avoid overmixing.
Fold in the chocolate chips.
Pour the batter into the prepared loaf pan and sprinkle extra chocolate chips on top.
Bake for 50–55 minutes, or until a toothpick inserted into the center comes out with only a few moist crumbs.
Let the banana bread cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.
Slice and enjoy!