01 - Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan or line with parchment paper.
02 - Whisk together mashed bananas, eggs, melted butter, Greek yogurt or sour cream, and vanilla extract in a large bowl until smooth.
03 - Combine flour, sugar, baking soda, salt, and cinnamon (if using) in a separate bowl.
04 - Add dry ingredients to wet mixture and stir gently until just combined. Do not overmix.
05 - Fold in chocolate chips, reserving a few to sprinkle on top if desired.
06 - Pour batter into prepared loaf pan and smooth top. Sprinkle reserved chocolate chips over batter.
07 - Bake for 50 to 60 minutes, until a toothpick inserted into center comes out with a few moist crumbs.
08 - Cool bread in pan for 10 minutes, then transfer to wire rack to cool completely before slicing.