Heat oil in a pan, splutter mustard, then add red chillies, urad dhall, hing, turmeric, curry leaves, and the chopped bittergourd. Sprinkle some water, and let it cook for 15-20 minutes. Now sprinkle taramrind powder or tamarind water, and salt. Simmer the stove and let it fry for a few more minutes until the oil seperates.