Ordinary Sambar

1/2 cup toor dal/pigeon peas
2 cups water
lemon-sized piece of tamarind pulp, soaked in 1 cup hot water for 15 minutes, drained
1 cup mixed vegetables, chopped into small pieces
2 green chilies, halved
1 cup water
salt
1/2 tsp turmeric
3 tsp sambar powder
1 tsp rice flour + 2 tbsp water (optional)
1 bunch cilantro, chopped

1 tbsp oil
1 tsp brown mustard seeds
1/2 tsp asafoetida powder
1/2 tsp fenugreek seeds
1/2 tsp cumin seeds
1 red chili, halved
a few curry leaves

Cook the toor dal in 2 cups water for 1 1/2 hours, stirring. Don't drain.
Heat the oil, add mustard seeds, asafoetida, fenugreek, cumin, chili, and curry leaves. When the mustard seeds splutter, add the green chilies and chopped vegetables. Saute a cople of minutes. Add the tamarind juicce, salt, turmeric, and sambar powder. Simmer on low until vegetables are tender. Add cooked dal, simmer 5 minutes. Add rice flour dissolved in water if necessary to thicken. Cook 2-3 minutes.

Source: Dakshin, Vegetarian Cuisine from South India by Chandra Padmanabhan