Pre-heat your oven to 180 C and place the rack in the middle of the oven.
Line your muffin pan with paper liners or parchment paper and lightly grease them.
In a mixer-grinder, powder the oats until they resemble fine meal. (You could even simply use oat flour but I usually just have oats in the house and I powder them).
In the same jar, add the flour, wheat bran, baking soda, baking powder and salt and give it a quick whiz to mix them up.
In a mixing bowl, place the pureed bananas, eggs, oil, maple syrup and vanilla extract. Using your hand beater, beat all the wet ingredients on high speed for about 2 minutes or until well combined and pale. Add the milk and give it another quick mix. You can do this step in your stand mixer as well.
Add the dry ingredients and fold using a wooden spoon or spatula until combined and no flour-y streaks are visible.
Add the chopped nuts, reserving a few for topping, and stir.
Spoon the batter into the muffin pan and top with the reserved nuts.
Bake for about 15 minutes or until a toothpick inserted into the centre of a muffin comes out clean. If they are not done at the end of 15 minutes, reduce the heat to 150 C and give it another 2-3 minutes before checking.
Remove from the oven and allow to cool in the pan for about 15 minutes. Lift the muffins out of the pan using the liners and stand on a cooling rack to cool completely, about 30 minutes.
Consume immediately or transfer to an airtight container and store in the refrigerator for up to 1 week.
Recipe by Food-Dee-Dum at https://food-dee-dum.com/2013/04/17/banana-bran-muffins/