Soak the tamarind in water and extract the essence and set aside.
Pressure-cook the green gram dhal.
In a heavy-bottomed vessel heat the oil; splutter the mustard and fenugreek seeds.
Add the slit green chillies and fry them well.
Add the tamarind extract along with salt, jaggery and asafoetida.
When it comes to a boil add the sambar powder and let it boil till the raw smell of the powder disappears.
Finally add the cooked dhal and let it boil together for a few minutes and remove from fire.