There are myriad versions of tomato rasam but the key to it is the balance between heat, sweetness and sharpness. Taste as you go and adjust the chilli, sugar and tamarind to your liking.
1 cup toor dal (pigeon pea)
1 teaspoon ground turmeric
6 small dried chillies
6 tomatoes, cubed
2 teaspoons tamarind pulp
1 teaspoon ground coriander
1 teaspoon ground cumin
4 teaspoons jaggery or caster sugar
½ teaspoon chilli powder, optional
oil, for frying
1 tablespoon black or yellow mustard seeds
12 fresh curry leaves
2 shallots, thinly sliced
2 cloves of garlic, thinly sliced
6 dried chillies, optional
Place toor dal, turmeric and dried chillies and 2 litres of water in a large saucepan and bring to the boil. Reduce the heat to a simmer and cook until the toor dal is soft. Occasionally skim the froth off the top.
Place a sieve on top of a large bowl and pour the dal into the sieve. Set ⅓ of the dal aside and discard the rest. Then pour the dal water back into the saucepan.
Add the chopped tomatoes, tamarind pulp, coriander and cumin. Bring to the boil, reduce to a simmer and place the lid on top. Cook for 20–25 minutes or until tomatoes have softened.
Add jaggery and salt to taste. Add chilli powder, if it requires extra heat. Using a stick blender or food processor, blitz soup until smooth. Add the reserved toor dal and heat through.
Heat the oil in a small sauté pan. Add the mustard seeds, curry leaves, shallots, garlic and dried chillies. Fry until shallots are golden and crisp. Add to rasam and serve. Serves 4.