- Preheat the oven to 350 degrees 
- If you haven't already mashed the bananas then add the whole bananas into a large bowl and mash until it forms into a pudding-like consistency. Then whisk together the mashed banana, eggs, vanilla, and coconut palm sugar until blended and smooth. 
- Slowly stir in the melted butter. 
- In the same bowl, on top of the wet ingredients, add the oat flour, baking soda, salt, and cinnamon. 
- Slowly stir just until all of the ingredients are combined, don't over mix. 
- Add the walnuts and stir 2-3 times until the nuts are evenly distributed. Don't forget to save a couple of tablespoons of the walnuts to sprinkle on top. 
- Spray a 12-cup muffin pan with cooking spray. Then divide the batter among the 12 muffin cups. Sprinkle the saved walnuts on top of the muffins. 
- Bake for 17-18 minutes. The muffins are done when you can insert a toothpick and there's no batter but only crumbs that stick to it. 
- Let the muffins cool in the pan for about 3 minutes. 
- Remove the muffins from the pan and place them onto a wire rack to finish cooling. Enjoy!