Rasam, also Saru, is a popular dish in South India. It can be described as a thin soup, served on top of rice.
- 14g (½oz) toovar dhal (also called red gram dhal)
- 1 teaspoon turmeric
- 1 teaspoon cooking oil
- 3 tomatoes
- 1 or 2 teaspoons of tamarind paste
- 1 teaspoon sugar (jaggery or palm sugar is good too)
- water - the amount depends on the amount of Rasam required. It is meant to be very watery.
Rasam Powder 
- 1 tablespoon coriander seeds
- 3 to 4 dried red chillies
- 1 teaspoon cumin seeds
- A small pinch of asafoetida
To prepare Rasam powder: Fry the all the ingredients together, adding asafoetida last, in a pan with two teaspoons of oil or ghee. Roast until the spices start to brown slightly, and powder the ingredients. (Coriander seed is very difficult to powder)
Mustard Seed seasoning 
- 1 tablespoon ghee (or butter and oil)
- 1 teaspoon black mustard seeds
- 1 teaspoon urad dhal (cumin seeds may also be used)
- 2 dried red chillies
- 4 curry leaves
- A handful of chopped coriander leaves (cilantro)
- Wash the toovar dhal thoroughly, until the water runs clear.
- Cover with double the quantity of water, turmeric powder and teaspoon of oil. Cook in a microwave for half an hour, a pressure cooker, or slowly on a stove, covered. The dhal should turn out a mushy consistency.
- Cut the tomatoes into four pieces, put them in a saucepan full of water and bring to the boil.
- Add tamarind, salt and teaspoon of sugar. The tamarind is usually very bitter, so add only a little at a time. Tamarind can be added later to adjust the flavour.
- When the tomatoes are half cooked add the cooked dal.
- Add enough Rasam powder to give the desired taste, usually 4 or 5 teaspoons. It should be reasonably spicy, and neither the tamarind or sugar should dominate. Stir and keep simmering.
- In a small pan, heat the ghee for the mustard seed seasoning and add the mustard seeds, urud dhal, chillies and curry leaves. The urud dhal should start to go brown and the mustard seeds will start spitting. Don't burn any of the spices - it's easy to do. Once cooked, pour the seasoning into the rest of the rasam straight away and stir it through.
- Add chopped coriander leaves. Serve with hot and soft plain boiled rice.
Karnataka Style 
- Pressure cook the dhal with sufficient water.
- If using tomatoes for sourness, parboil first to remove skin and chop roughly.
- To the cooked dhal, add salt, chilli powder, turmeric powder, and tomatoes or tamarind extract.
- Simmer for 3 to 4 minutes.
- Add the asafoetida, grated coconut, and ground coriander.
- Add any other spice as required (please list the optional spices or ingredients!)
- Simmer for a few minutes (to cook the coconut properly).
- In a separate frying pan, heat 3 tablespoon of oil over medium heat.
- Add the mustard seed and cumin seed.
- When the mustard seeds pop, remove from the heat and add the curry leaves.
- Add to the Saaru.
- Garnish with coriander leaves.