In a non stick pan, heat oil. Put bengal gram dal and saute for some time. Add red chillies and fry. Then add asafoetida, chopped tomatoes and turmeric powder. Keep on sauting the mixture for a few minutes. Switch off the flame. Let it cool.
After the mixture cools down, grind it and add salt.
In a kadai, heat oil for tempering. Once hot add mustard seeds, urad dal and curry leaves. Put the tempering in the tomato paste