Soak the channa dal in the water for 1 hour.
Drain the water and add red chili, asafoetida, curry leaves and salt.
Grind all these items in the blender (not powdery). with little water. Now take small amount and make small balls.
Boil 3 cups of water in the Idli Vessel, drop the balls in the idli pots and steam it for 8 minutes.and keep it aside.
Heat the pan with the oil and fry mustard seeds, cumin seeds, curry leaves and then add the chopped onion and fry for 2 min, then fry tomato and add the tamarind juice, sambar powder, salt and mix well.
Now add the steamed channa dal balls into it. Cover the pan and let it boil in the medium heat.
Remove the cover and let it to boil for 5 min.