Wash the split pigeon peas. To a vessel add the lentils, tomatoes and green chillies. Pressure cook until soft. Set aside to cool.
Add water to tamarind and set aside for it to soften. After 10 min, squeeze the tamarind water and keep aside.
Mash the lentils to slightly coarse. Add the tamarind water, salt, turmeric, red chilli powder and bring it to a boil, and them simmer for 5 min. Turn off the heat.
Take a pan and add ghee, cumin and mustard seeds. Saute for a 2 min until they sputter.
Add red chillies, garlic , curry leaves and asafoetida.
Add the tempering to lentils and mix well.
Serve hot with rice and ghee.