Preheat the oven to 190 degrees C. If you have fan forced – 180 degrees C.
Grease the muffin tray or place in muffin cases.
In a large mixing bowl, mash the bananas with a fork or potato masher until the banana is super mushy.
Add the eggs, and whisk. Add the sugar and stir to combine.
Pour in the milk, apple cider vinegar and oil then stir to combine.
Add in the dry ingredients of flour, oat bran, baking powder, cinnamon and salt and stir to combine.
Pour the muffin mixture into the muffin tray filling to 3/4 of the way up.
Bake in the oven for about 20 minutes or until they "bounce" when you press the top of the muffin. You can also check they are cooked by inserting a skewer into the muffin if the skewer comes out clean.
Remove from the oven and transfer to a cooling rack to cool.