Soak tamarind and salt in 1 1/2 cup water. Take out the tamarind juice.
Heat a teaspoon of oil in a kadai and add fenugreek seeds. When they turn brown add red chillies, toor dal, channa dal, asafoetida and urad dal and fry. Cool it and grind them into powder along with little salt.
Slit the brinjals into four keeping the bottom in tact. Stuff the ground powder into the brinjals.
Heat remaining oil in a kadai and when it is hot add mustard seeds. When it pops up add curry leaves and the brinjals. Reduce the heat and close with lid. After few minutes, add the tamarind water, turmeric powder and sambar powder. Close with lid and allow to boil. Reduce the heat and cook till the kuzhambu thicken.