If necessary, grease all 12 cups of your muffin tin with butter or non-stick cooking spray
In a large bowl, mix the olive oil and maple syrup together with a whisk
Add the eggs and combine thoroughly
Mix in (in order) the mashed banana, milk, baking soda, vanilla extract, salt, and cinnamon
Add flour and oats and mix with a large spoon or spatula
(Optional) Add any mix-ins like nuts, chocolate chips, or dried fruit
Preheat the oven to 325 degrees Fahrenheit
Divide batter evenly between muffin cups
Sprinkle tops of the muffins with any desired toppings (oats, cinnamon, turbinado sugar, etc.)
Bake for 22-25 minutes until an inserted toothpick comes out clean