Take half cup of milk (room temperature) in it add vinegar. Mix it well and meet it aside. Now take 2 medium sized bananas & peel them.

Cut the bananas into pieces. Now take a large bowl and add the banana pieces in it. Then add sugar, oil & vanilla essence. (Note: You can add any essence of your choice) Now blend it into a smooth paste as shown in the image.

Now keep a strainer over the bowl and add maida, cocoa powder, baking powder and baking soda. Strain them and mix everything well.

Now add the buttermilk to it which we have kept aside (milk + vinegar mixture). Mix everything very well.

Now to it add white chocolates & milk chocolates, again mix them well. Now grease a cake tin with oil, then add the cake batter to it. Tap it gently twice to remove the air-bubbles from it. Now put some shredded white chocolate over the batter.

Now take a kadai for pre-heating with it's base covered with salt and a stand over it. Cover it and pre-heat the kadai for 3 mins on high flame and then 7 to 8 mins. on medium flame.

After 8 mins, remove the lid and place the cake tin over the stand and cover the lid again. Now bake the cake for about 50 mins on low flame.

After 50 mins, remove it from the kadai, let it come to the room temperature, then demould it, cut them into pieces & serve it.