MethodWash the yam, remove the skin and cut into small cubes. Keep aside.Grind the coconut to a fine mixture. Keep aside.Heat the ghee in a pressure pan, add the cumin seeds, green chillies,saute for a minute.Add the yam, coconut paste, water, kokum or tamarind and salt, mix well and cook in the pressure pan for 10-15 minutes on a medium flame.Serve hot and garnish with coriander.