Preheat your oven to 350°F (175°C) and grease a muffin tin or line with muffin liners.
In a large mixing bowl, mash the ripe bananas until smooth.
Add the melted coconut oil and honey (or maple syrup) to the mashed bananas and whisk until well combined.
Beat in the eggs, then add the milk and vanilla extract. Mix well.
Sprinkle the baking soda, salt, and cinnamon over the wet ingredients and mix until combined.
Gently fold in the whole wheat flour and oats until just combined. Do not overmix.
Divide the batter evenly among the muffin cups, filling each about ¾ full.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.