Preheat & Prep. To start, preheat oven to 350 degrees F. Line a 12-cup muffin tin with parchment muffin cup liners or grease muffin cups.
Combine Wet Ingredients. In a food processor (or stand mixer), combine bananas, coconut oil, syrup, almond milk, eggs, and vanilla. Puree until smooth.
Mix In Dry Ingredients. Add flour, baking soda, cinnamon, and salt to the wet ingredients. Pulse until just combined. Use a spatula to fold in 1/2 oats and stir in mix-ins (if using).
Scoop Muffin Batter. Then, scoop or spoon the batter into the prepared muffin cups, filling them most of the way full. If desired, sprinkle them with a few quick oats on top.
Bake muffins at 350 degrees for 18-20 minutes, or until the tops are golden and a toothpick inserted in the center comes out mostly clean with a few moist crumbs. Allow muffins to cool 1-2 minutes in the muffin pan before transferring to a wire rack to finish cooling down.
Serve & Store. Enjoy right away, or store leftover muffins in an airtight container in the refrigerator or a freeze in a freezer bag up to 2 months, for best results.