Wash the toor dal several times in water until it runs clear. Then add it to a pan along with around 600 ml water, bring it to a simmer and cook until completely soft (45 minutes). Use a potato masher to mash it into a thin porridge.

While the dal is cooking, soak the tamarind in 150 ml boiling water for 15 minutes. Then massage the tamarind between your fingers to remove it from the fibres and filter the juices through a sieve.

For the sambar powder, trim the chillis and shake out as many seeds as possible, then toast the deseeded chillis in a small frying pan until they just begin to char, then set aside. Next, toast the seeds and black pepper until aromatic. Add the curry leaves and continue toasting until they are crisp, then set aside. Finally, toast the chana and urad dal until golden and set aside as well. Let them cool off slightly, then transfer everything to a spice grinder along with the turmeric and asafoetida and grind into a fine powder.

In the meantime, peel the shallots and cut them in half. Trim and half the chillies. Roughly chop the rest of the veg into pieces as big as the shallot halves. Roughly chop the coriander. Heat some oil in a sauce pan and sauté the shallots for just a minute. Add the tomatoes and chillis and sauté for another minute. Then add the rest of the veg along with 500 ml water, the turmeric and 1 1/2 tsp salt. Bring to a boil, cover and simmer for around 10 minutes until the veg are just getting soft. Add 2 tbsp of the sambar powder, followed by the tamarind juice, then add the mashed dal and bring everything back to a boil. Turn off the heat.

For the temper, add the oil to a small pan. Once hot, add the mustard seeds and fenugreek seeds. When they begin to sizzle vigorously, add the chillis followed by the curry leaves and, as soon as the leaves turn crispy, the asafoetida. Pour the temper over the sambar followed by the chopped coriander and cover with a lid to let it infuse for 2 minutes. Give it a good stir and serve together with idli or rice.