Preheat your oven to 350°F. Spray a loaf pan with cooking oil spray and set aside.
Mash the bananas in a large mixing bowl until smooth. Measure to ensure you have the right amount as baking is a science!
Mix in the wet ingredients, including olive oil, milk, and vanilla extract. Stir until well combined.
Add the dry ingredients: oat flour, all-purpose flour, baking soda, cinnamon and salt. Stir gently until just mixed. Be careful not to overmix.
Fold in the chocolate chips.
Pour the batter into the prepared loaf pan and spread evenly. Add a few additional chocolate chips on top, if desired.
Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean. Do not open the oven to check before or your banana bread will fall!
Let cool in the pan for 10-15 minutes, then transfer to a wire rack to cool completely.