1. Wash and soak bengal gram dal and red gram dal in water for some 2 hours.
2. Grind it to a paste adding very little water along with cumin seeds and red chillies.
3. Two red chillies and cumin seeds should be soaked along with dal.
4. Next we have to clean and cut the vegetable into 1/2 inch size.
5. Pressure cook or microwave adding little salt.
6. Heat oil in a pan/kadai, add asafoetida, splutter mustard seeds, cumin seeds, red chillies, curry leaves, black gram dal and fry for some time.
7. Then add chopped onions add very little salt and fry for some time.
8. Meanwhile the grinded dal should be kept in idly cooker or in an ordinary cooker keeping piramanai or a stand and keeping a plate over which the grinded dal should be spread over.
9. Once it is boiled split it over hand and add to the kadai.
10. Add the boiled vegetables and fry for some time.
11. Kothavarangai paruppu usili is delicious and ready to be served.

Courtesy: http://tamilveg.blogspot.com/