Start by mashing the bananas with a help of a fork. It can have some chunks if you like its texture.
Along with this add egg, melted butter, brown & white sugar, and beat well with a beater or hand blender.
Then add milk, vanilla essence, all-purpose flour, baking powder, and baking soda and fold the mixture gently.
With this mixture add grated chocolate or chocolate chips and chopped walnuts.
Pour the batter in a greased cupcake tray or on muffin moulds.
Preheat the oven to 180°c and bake the muffins for about 20 to 25 minutes or until done.