After frying the vadas, let them cool and come to room temperature.
Then, soak them in lukewarm water for about 1 hour.
In a mixing bowl, combine whisked curd/yoghurt and salt.
In a mixie jar, make a paste of coconut, green chillies and ginger. Add a little water to aid in grinding.
Add this prepared paste to the yoghurt.
In a pan, heat oil. On medium heat, fry cumin seeds, mustard seeds and dry red chillies.
Once the mustard seeds start crackling, turn off the heat and add this tempering mixture to the yoghurt.
Give everything a good mix.
Now, gently press the vadas between your palms and squeeze the excess water out.
Add them to the yoghurt mixture. Cover completely with yoghurt.
Fry curry leaves and chop coriander leaves. Garnish curd vada with them. Also sprinkle red chilli powder.
Cover and let it rest for about an hour. Then serve.