Heat a nonstick pan with oil. Add the sambar tempering whole spices along with curry leaves. Saute for couple of minutes. Add hing and slit green chillies. Saute everything and add the chopped spring onions, sambar onions.
Cook everything for 3 minutes. Add the chopped tomatoes. Add the sambar powder and salt. Add the tamarind pulp. Combine everything and let it simmer for 5 minutes.
Add the cooked dal along with drumstick. Add water as required and bring to a boil.
Cook for 10 mins on low flame, finally add the chopped coriander leaves.
Serve with rice.