2Melt butter in a mixing bowl, add sugars and cream together. Whisk in the egg, and mashed bananas.
3In a separate bowl, mix flour, baking soda, baking powder, salt and cinnamon together and then stir them into the banana mixture. The batter might be a little lumpy from the bananas, but stir until it appears to be smooth.
4Pour batter into a greased muffin tins and bake 20-22 minutes.