1. Pressure cook the tuvar dal (you can add a little bit onions, green chilly and tomatoes to the dal, i dint do that this time).
2. Chop the veggies into small pieces.
3. Heat a pot with some oil. once hot, add mustard seeds. once it splutters add hing, curry leaves and green chilly.
4. Saute it for few seconds. now add chopped onions. cook it until it's light brown.
5. Now add the chopped tomatoes, the chopped veggies. add water, salt and let it cook for 2 minutes.
6. Now add the tamarind pulp and cook it until the veggies are soft.
7. Add the cooked dal.
8. Grind the ingredients "to grind" heading to a smooth paste and add it to the cooking pot of sambar. cook for 3 to 4 minutes, turn off flame.
Serve piping hot with idly or dosa.
I added all these veggies, you can just add any veggies which is in the fridge.