Preheat oven @180° for 10 mins. Grease a cake pan with oil and keep aside.
In a mixing bowl add the ½ cup muesli, milk, sugar and stir them. Keep side and make the other ingredients ready.
Peel the banana skin and mash with a help of a fork or a masher. Keep aside.
In another mixing bowl sieve the flour, baking soda, baking powder and mix them well together.
In the muesli mixture add oil, vanilla essence, mashed banana and mix well.
Now add the dry ingredients to the wet ingredients and make a lumps free mixture.
Pour the mixture into the greased pan and tap the cake pan for 2-3 times to release the air bubbles.
Sprinkle the remaining muesli over it. Bake for 35-40 mins. A toothpick inserted should come out clean.
Remove from the oven and let it cool down for 5-10 mins. Demould and let it cool down completely. Cut and serve.