Beat sugar,refined oil and curd in a bowl with a blender.
Gently add maida,vanilla essence,baking powder and baking soda.Use milk if required.
Use cut n fold method to mix it nicely without lumps.
Divide it into 2 equal parts.
Mix cocoa powder in 1 half and part will remain as it is.
Grease a tin.pour white part in a tin.Tap gently.
Now softly pour chocolate part on white part.
Again tap gently.
Keep it in micro for 35-40mins at 180°
Or..in cooker for 50 mins removing its whistle and gasket..
Let it cool ..then cut it into slices.