Method

Pressure-cook toor dal with turmeric and 2 cups water for 3 whistles until completely soft and mashable. Mash well. Meanwhile, boil tamarind pulp with vegetables in 300ml water for 8 minutes. Add sambar powder, tomatoes, and jaggery. Cook 5 minutes.
About 15 min
Tip: Over-cook the dal to a completely smooth consistency — lumpy dal makes a thick, unpleasant sambar.
Add the mashed dal to the tamarind-vegetable base. Stir well. Adjust consistency with water (sambar should be flowing but not watery). Simmer 8 minutes. Taste and adjust salt, tamarind, and sambar powder balance.
About 10 min
Tip: The balance of three elements — tamarind (sour), sambar powder (spice/depth), jaggery (sweet) — defines a great sambar. Taste and adjust each one.
Make tempering: Heat coconut oil in a small pan until smoking. Add mustard seeds (let pop), dried red chillies, shallots (fry until golden-brown), curry leaves, and asafoetida. Pour this sizzling tempering into the sambar. Cover immediately to trap the aromas. Serve with idli, dosa, or rice.
About 5 min
Tip: The tempering should go in last, very hot, and the pot should be covered immediately so the aromas bloom inside the sambar.

Nutrition per serving (estimate)