Preheat oven to 350 degree Fahrenheit.
Peel and mash the bananas and keep it aside.
In a large bowl, mix together the dry ingredients - flour, baking powder and baking soda.
In another bowl, mix together the melted butter and sugar.
Add the eggs to the butter sugar mixture and beat the mixture well using a balloon whisk for best results.
Add the vanilla extract to the egg butter sugar mixture and mix using a spoon.
Add the mashed bananas and the egg butter sugar mixture to the dry flour mixture.
Mix all ingredients together, you may use a balloon whisk or mixer to blend the ingredients and to avoid any lumps. It is important not to over mix the ingredients, just mixing for few seconds is enough.
Grease a cake pan with butter and pour the cake batter in to it.
Bake for about 40 minutes or until a toothpick inserted in the center of the cake comes out clean. In case the top of the cake browns before the inside is completely cooked, cover the top with aluminium foil and bake for the rest of the time.
Allow the cake to cool in the rack.
After cooling the cake completely, you may apply any frosting or enjoy the cake as it is!