Soak Dal for 3 hours. Grind along with two green chillies and salt. Make vada out of it. Beat curd add salt and sugar. Take oil in a small Pan add Hing, mustard seeds, whole red chilli, curry Patta, saunf. Allow it to crackle. Add this to beaten curd after sometimes add fried vada and little more water. Soak Vada for 1 hour then serve.