Mash the ripe bananas nicely and add sugar to it.Mix it thoroughly.Add eggs one at a time and mix well.Add melted butter and cream it well.Sieve the flour,baking powder,baking soda and add to the banana -egg mixture .Fold into the mixture till smooth.Add raisins,vanilla essence and cinnamon powder and fold it nicely.Scoop the batter into the muffin cups,not exceeding two-third of the cup.Sprinkle oatmeal on top of it.Bake in a preheated oven at 425 degree F for 10 minutes or till it springs back on touch.