1. Preheat the oven to 325 degrees Fahrenheit (165 degrees Celsius). If necessary, grease all 12 cups of your muffin tin with butter or non-stick cooking spray (my pan is non-stick and didn’t require any grease).
2. In a large bowl, beat the coconut oil and maple syrup together with a whisk. Add the eggs and beat well. Mix in the mashed bananas and milk, followed by the baking soda, vanilla extract, salt and cinnamon.
3. Add the flour and oats to the bowl and mix with a large spoon, just until combined. If you’d like to add any additional mix-ins**, like nuts, chocolate or dried fruit, fold them in now.
4. Divide the batter evenly between the muffin cups, filling each cup about two-thirds full. Sprinkle the tops of the muffins with a small amount of oats (about 1 tablespoon in total), followed by a light sprinkling of sugar (about 1 teaspoon in total). Bake muffins for 22 to 25 minutes, or until a toothpick inserted into a muffin comes out clean.
5. Place the muffin tin on a cooling rack to cool. You might need to run a butter knife along the outer edge of the muffins to loosen them from the pan. These muffins will keep at room temperature for up to 2 days, or in the refrigerator for up to 4 days. They keep well in the freezer in a freezer-safe bag for up to 3 months (just defrost individual muffins as needed).