Take the Yoghurt in a container and add little water and make it like like a uniform paste. Add methi seeds, turmeric powder, salt and keep it aside. Grind coconut, cumin seeds and green chillies in a blender and make a paste. Add the paste to the yoghurt. Keep it in the stove for a little while until nice foam comes up on the surface. Switch the stove off. (if you over cook it yoghurt will get denaturated in to water) then season it with mustard seeds, cumin seeds, curry leaves and coriander leaves. Good for Rotis as well as Rice. Excellent to go with Paruppu Usli. Don't reheat it.