Preheat oven to 170°C

Mix all dry ingredients, flour, baking powder, baking soda and cocoa. Keep aside.

Melt butter, add the sugar and mix until creamy.

Add vanilla extract, eggs and sour cream (use danone's vanilla flavoured yogurt instead of sour cream for better taste). Mix well untill smooth.

Now mash the bananas and add in the wet mixture. Mix well.

Add the dry mixture into the wet mixture and mix well untill smooth. Add milk for proper consistency if required.

Add the chocolate chips in the batter and mix well.

Grease medium sized muffin cups, fill the batter 3/4 in d cups.

Bake for 10 to 12 minutes or untill an inserted toothpick/ knife comes out clean.