Pressure cook tuar dhal softly with 1 cup water for 4 or 5 whistles.
Cut ginger into small pieces. Crush cumin seeds, black pepper and garlic coarsely.
In a pan - Mash the dhal nicely and add about 2 cups water.
To this add slit green chillies, ginger, the coarsely crushed cuminseeds, black pepper, garlic and turmeric powder.
Extract the pulp from tamarind with 1 cup of water.
Aadd this to the dhal and bring it to a boil and take it off the flame.
To garnish the above heat add the oil and then add mustard seeds.
when they splutter add the broken red chillies and curry leaves.
When they are crisp add asafoetida to this and add this to the above rasam.
:- It tastes good with rice.