I just made it on stove it took one hour with low flame you can use oven accordingly your experience

beat eggs add butter and 1 cup of sugar and mix well

put baking powder and baking soda in flour

peel off bananas and shake them with milk

put banana shake in beaten eggs mixture

now add banana mixture in flour and mix them well at 5 minutes

now take another bowl and put half mixture in the bowl

add cocoa powder in half mixture

now take baking bowl brush inside with butter

now put one spoon of batter in baking bowl then put one spoon of cocoa mixture

repeat this way till the bowl full and bake