Preheat your oven at 180c

Firstly in a bowl mix curd,oil, baking soda and baking powder and whisk it well

In time being grease with oil/ butter your cake tin

Then sieve your all purpose flour in another bowl

Then add sugar to your curd mixture

Add all purpose flour slowly...mix and fold it.. don’t whisk it

Now divide the mixture in two equal parts

In one part sieve and mix cocoa powder

If you feel your mixture is very thick u can mix little milk for the correct consistency.. not too thick not too thin
Now lastly add in your thin first 2 tsp of vanilla (white) mixture and followed by 2 tsp of chocolate mixture.. now follow the same till end.
Now put this in the for 30 min check by tooth pick