Wash the toovar dal and boil with turmeric powder. When the dal is tender churn it completely. Dissolve the tamarind paste in 2 cups water. Heat 1 tbsp of oil in a small pan, add 2 red chillies, coriander seeds, chana dal, 1/2 tsp fenugreek seeds and sauté for 2 minutes. Cool and grind to a paste. Sauté coconut in the remaining oil and grind to a fine paste.
Mix the masala paste with tamarind water, chopped brinjals, green chillies and curry leaves. Add this into the mashed dal along with more water if required. Cook this on a low flame till it starts boiling. Add coconut paste and continue cooking on a low flame till the gravy thickens slightly.
Heat oil in a small pan, add mustard seeds, remaining red chillies, fenugreek seeds and asafoetida. When the seeds start crackling add into the dal. Cook for 2-3 minutes. Serve hot with steamed rice.