1. Heat 2 tsp of oil and add all dry items mentioned for the spice paste.
2. Fry dals till they turn light brown and chillies turn bright red.
3. Grind into a coarse paste along with the tomato. Keep aside.
4. Mix tamarind paste in 2 cups of water and boil for around 10 mins.
5. Add spice paste and boil it for another 10 mins. Keep stirring.
6. Add some water if the kuzhambu seems too thick.
7. Remove from heat once the raw smell of tamarind goes off. Keep aside.
8. Heat 1 tbsp of oil and add mustard seeds.
9. Add sundakkai once mustard stops crackling.
10. Toss it for about half a minute and add the curry leaves.
11. Pour it over the kuzhambu and serve.

Recipe courtesy: foodiliciousnan