Add turmeric to this and add 1 1/2 cups of water and boil until the raw smell goes from the tomato.
Crush cumin seeds, black pepper and garlic coarsely and add this to the tomato.
Extract the pulp from the tamarind and make about 1 cup of extract.
Add this to the tomato water.
Add the coriander powder and red chilli powder and add about 1 cup of water.
:- If you have cooked red gram, then crush it nicely in about 1/4 cup water and add this.
Bring this to a boil and add the coriander leaves and take it off the flame.
To garnish, heat oil and then add mustard seeds. When they splutter, add broken red chillies and curry leaves. When they turn little crisp, add asafoetida and add this to the above rasam.
:- Rasam is ready!!!
:- If you do the garnish in little ghee instead of oil, it gives a different flavour and smell.