Sprinkle this over dahi vada and keep it in the fridge for half an hour (so that the vada gets soaked in curd).
:- Thayir vada / Dahi vada is ready to serve.
Option II:-
1)Instead of sugar, beat the curd by adding salt, little chilli powder(say 1/2 tsp), 2 pinches of asafoetida and 2 pinches of cumin powder.