For Rasam Powder:-
1)Roast the pepper corns, coriander seeds and dry red chillies and keep aside.
After roasting coriander seeds, add coriander leaves to it until the moisture is out of the leaves.
Let it cool.
Powder all the above in a mixer and store it in a dry and moisture free container.
For Rasam:-
1)Cut tomatoes into small cubes.
To the above chopped tomatoes, add turmeric powder, salt and chopped coriander leaves and keep aside.
Pressure cook dal well and mash it.
Heat a pan (without oil).
Add rasam powder along with the mixture of tomato, turmeric, coriander leaves and salt with 1/2 cup water and set to boil.
To this, add tamarind extract and stir well.
When the tomatoes are well cooked, add dal and more water depending on the consistency you require.
Keep on medium flame and set it to bubble up.
Just as it bubbles up on the sides, turn off heat and season it with mustard seeds, curry leaves and asafoetida.
Close it with a lid immediately so that not to lose the aroma.
:- Serve with hot rice and pappad.