Preheat the oven at 350°F.
Wash and peel the bananas.
Place the bananas in a bowl and mash to desired consistency (chunky or smooth).
Melt the butter in the microwave for 30 seconds to 1 minute.
Add melted butter and sugar to the mashed bananas. Mix.
Crack the egg and whisk fully.
Add the whisked egg and vanilla essence to the batter. Mix.
In a separate bowl, incorporate the dry ingredients - flour, baking powder, baking soda, and cinnamon powder.
Combine the dry and wet ingredients together.
Mix thoroughly so there are no flour lumps in the batter.
Line muffin trays with baking cups.
Place batter into the cups until they are 3/4 filled.
Bake for 22 minutes.
Remove from oven, check for doneness and place on a cooling rack.
Serve.