Soak tamarind to extract juice. Slice beetroot & cook it. Grind cooked beets with rasam powder & coconut with water. Boil the tamarind extract with salt,turmeric & green chilly. Add the ground mixture & boil for a while. For Seasoning, heat 1 tsp of oil & add 1/2 tsp of mustard seeds & 1 red chilly. When it splutters, pour it over the rasam.