Melt the butter and honey together over a medium heat. Add the vanilla and leave to cool.
Meanwhile mash the bananas well.
Mix the flour, bicarbonate of soda, baking powder and cinnamon together.
Mix the butter and honey with the bananas, then stir into the flour mixture.
Add the fudge chunks and stir through well.
Divide the mixture between 6 large or 10 small muffin cases.
Bake in the oven at 190 deg c (lower for fan ovens) for around 15-20 minutes, until springy to the touch. Remove from the pan and leave to cool.