It is impossible to list how many cupcake recipes there are. Probably, even every chef and housewife has his own brand, which he invented himself or improved familiar to everyone.
Wash bananas, peel and puree with a blender or fork.
Melt the butter, add it to the puree along with sugar, sifted flour, baking soda, baking powder, and eggs. Knead the dough.
Pour the dough into a baking dish. Place the muffin to bake in the oven at 180 degrees for 50 minutes. Serve the pastries by turning them over and sprinkling with powder.