Rasam, I find, is one of those things that you can't cook by recipe alone. There has to be a feel for the dish, an innate sense of what and how much goes in. I've always been a cook of proportions, preferring to follow recipes, and so, my rasams were never fabulous (or ever measured up to what I had growing up).

A friend gave me a cookbook when I left for the US to study, and said "read it when you are feeling homesick". I didn't take it out for almost 3 months and then one day, I desperately wanted rasam. I tried this book and it was the best I've ever had.
Rasam is a thin, slightly spicy soup with a lentil base. It is delicious mixed with rice, but tastes as good just as a drink.
Mysore Rasam (adapted from Dakshin by Chandra Padmanabhan)
1/2 cup red gram dal or masoor dal
3-4 small tomatoes, quartered
3 tsp Mysore Rasam Powder (recipe follows)
2 tbsp jaggery, powdered (I use sugar and it tastes as good)
1/4 tsp turmeric powder
1/2 cup coconut milk
1 small bunch coriander leaves, chopped
1 tsp juice of tamarind
salt to taste
For tempering:
1 tbsp ghee
1 tsp mustard seeds
1 tsp cumin seeds
1 red chilli, halved
1/2 tsp asafetida powder
a few curry leaves
Procedure:
Heat the oil and add the tempering ingredients. When the mustard starts to splutter, add the tomatoes, jaggery/sugar, tamarind extract, mysore rasam powder, salt and turmeric.
Keep on a low flame and let it simmer until the raw tamarind smell disappears. Add the cooked dal and let it simmer for another 5 or so minutes. Add the coconut milk, coriander and remove from heat.
Mysore Rasam Powder2 cups dhania or coriander seeds
1/4 cup peppercorns
1/4 cup cumin seeds
4 tsp fenugreek leaves
1 bunch curry leaves
2 cups red chillies
3 tsp oil
2 tsp turmeric powder
Roast the coriander seeds, peppercorns, cumin, fenugreek and curry leaves on a dry pan.
In another pan, fry the red chillies in the oil.
Combine all the ingredients and grind to a fine powder.