Cook beetroot until soft. You can do it either on stove top by peeling off the skin and boiling in water, or pressure cook it or microwave it.
Once done, cube and keep aside.
Soak tamarind in hot water, extract juice, add water and make it total 4 cups.
Roast the ingredients under ‘To roast & grind’ table in order. Cool down and grind it with the cooked beetroot and little water to a paste.
Boil the tamarind water, say for 3 mins, add the ground paste, rasam powder if using, salt, jaggery, turmeric, slit green chillies. Mix well.
Let it froth and boil for a minute. In a kadai, heat oil, temper with the items given under ‘To temper’ table and add it to the rasam, mix well.