First mash the bananas with a fork. Then put all the ingredients in a mixing bowl and mix well with a hand mixer. Grease the muffin tray well and then fill in the batter. Bake in a preheated oven at 180° C for 25-20 minutes.
The muffins can be spiced up with apple pieces, blueberries or raspberries, raisins, nuts or seeds, according to your liking.