In a mixing bowl, add the banana and mash with the back of a fork until smooth. Add the remaining ingredients and stir until well combined. [Tip: If you have berries on hand, feel free to fold some into the batter.]

Let the batter rest for 5-10 minutes while you preheat the oven to 350°F (175°C).

Lightly spray a muffin tin with cooking spray. Divide the batter evenly among the muffin cups, based on the number of muffins listed in the recipe serving details.

Bake for 13-17 minutes, or until the muffins are set and lightly golden on top.

Allow to cool completely before storing. Store in an airtight container in the refrigerator for up to 4-5 days, or freeze for longer storage.