Cook thuar dhall with 2 cups of water and keep it aside. Boil tomatoes in 1-2 cups of water, then add tamarind paste, hing, salt, and turmeric. After tomatoes are cooked, add rasam powder, and let this boil for five minutes. Now add thuvar dhall and let it cook for a few more minutes. Heat some ghee, splutter mustard, then add pepper powder and cumin powder to this before mixing this with the rasam. Garnish with chopped cilantro.