Soak tamarind in warm water and keep aside. Peel and cut beetroot into medium size cubes. Add salt and water and pressure cook the beetroot for 2-3 whistles.
In another pan, heat coconut oil, fry cumin and coriander seeds and keep aside. Then fry the urad dal, chana dal and chillies. Once cooled, add everything along with coconut to a grinder and grind to a smooth paste.
Add the tamarind water and jaggery, if using, to the beetroot curry. Add the masala paste and bring the curry to a boil. Let it simmer, until the masala is cooked
For tempering, heat some oil, fry mustard seeds, fenugreek seeds and curry leaves and pour it over the curry. Serve with some hot rice or rotis.