Preheat the oven to 400 degrees, and prepare a muffin tin with liners or cooking spray.
In a bowl, whisk the bananas, oil, sugar, vanilla, and eggs until combined. Add the chocolate chips. Add the flour, baking powder, baking soda, salt, and cinnamon. Stir just until combined.
Scoop the batter into the muffin tin. Bake for around 15 minutes, or until a toothpick inserted in the center comes out clean.