Mix the butter and sugar together until light and fluffy.
Add the egg, stir. Then add mashed banana and mix to combine.
Sift in the self-raising flour and baking powder, then fold to incorporate.
Add in a few dashes of cinnamon, and ½ tsp of vanilla
Grease a loaf tin and pour in the batter, smoothing the top.
Cook in the air fryer at 325°F (160°C) for 35 minutes. (325°F if using a disposable tin?)
Allow to cool completely before slicing.
