1. Wash and soak both dals along with one red chilly and cumin seeds for an hour and grind them to a coarse paste.
2. Add only little water.
3. Pour the paste in idly plate and pressure cook it.
4. Then split into small pieces with hands.
5. Heat oil in a pan/kadai, splutter mustard seeds, cumin seeds, curry leaves, red chilly, add little asafoetida and add the dal.
6. Mix them well adding little salt.
7. Fry them for some 5-10 minutes.
8. Paruppu usili is delicious and ready to be served.
9. It can be served with any rice item. Vegetables can be cooked and added to this.

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