Heat gingilly oil in a thick bottom vessel add mustard seeds let it sputter add red chillies, toor dal (optional) and asafoetida.
Add onion, fry till turns golden brown
Pour tamarind extract add sambhar powder, turmeric powder and salt allow it to boil, after some time add jaggery. Boil further till it becomes thick (approximately a little less than half the taken quantity of tamarind extract) Garnish with curry leaves.