Ingredients:

Sambar dhal - 11/4 cup
Vegetables like brinjal,ladies finger, potato, carrot, tomato etc.        - 1 cup each
Chopped onions - 1
Green chillies - 5
Turmeric - 1 tsp
Salt    - To taste
Tamarind  - 5gms to 10gms

To be ground:
Coriander seeds - 11/4 dsp
Dry chilies - 14
White gram dal - 1 dsp
Fenugreek - 1 tsp
Grated coconut (optional)- 1/2 cup
Asafoetida - 1 tsp 
Oil -2 tsp

To season
Oil - 3 dsp
Curry leaves -2 sprigs
Mustard - 1 tsp
Broken dry chilies - 4
Fenugreek- 1 tsp

Method:

Cook the dal, add the sliced vegetables, onions, chillies salt and boil. Meanwhile roast the ingredients of the masala in 2tsp of oil and grind it. Add the turmeric and the masala to the dal and vegetables and boil for some time. Fried and powdered fenugreek and asafoetida are added. Season with mustard, chillies and curry leaves in oil. To add the taste little tamarind water is poured into the sambar. 

lnstant sambar powders are also available in the market.