HOW TO COOK :
Heat oil in a kadai, add mustard seeds, urad dhal, dried red chillies, curry leaves, sliced tomato and saute.Then add 20g rasam powder. Mix well. Add one litre water and allow it to cook for sometime.Then prepare 1 litre of tamarind juice and keep it aside. Then add salt. Check for the seasoning. Top with chopped coriander leaves. Remove from heat before it starts boiling vigourously. Serve hot.