make juice of 4 sweet lime and keep it ready.
boil tamarind in 4 cups water. boil it and keep it aside until use.
heat ghee and oil and crackle mustard seeds.
add asafoetida, turmeric powder, cumin seeds, crushed ginger, curry leaves and coriander leaves, green chilli.
fry for half a minute.
immediately add boiled tamarind water, chilli powder, sambar powder, cooked and mashed tur dal, salt, rasam powder and mix well.
let the rasam come to a boil. When it starts to boil, switch off and add the sweet lime juice.
serve hot with rice