Preheat oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment paper.
Mash bananas in a large bowl until smooth. Stir in melted butter, cane sugar or maple syrup, eggs, and vanilla.
In a separate bowl, whisk together flour, baking soda, baking powder, salt, and cinnamon (if using).
Gradually fold the dry ingredients into the wet ingredients until just combined. If using, stir in Greek yogurt or sour cream.
Mix in chocolate chips if desired, then pour the batter into the prepared loaf pan.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Cool for 10 minutes in the pan, then transfer to a wire rack to cool completely.