Meanwhile, in the inner pot of an IP, add a tsp of oil. Once it becomes hot, on saute mode, add coriander seeds, chana dal, red chillies.
Saute until colour changes slightly and a nice aroma comes. Cancel Saute mode. Add asafoetida, cumin seeds & fenugreek seeds.
Just saute for a minute in the heat of the pan. Keep it aside. Once the ingredients come to room temperature, powder them.
In the same pot, add ghee /oil. Once hot add mustard seeds, red chilli, curry leaves. Once mustard splutters, add green chilli followed by small onions. Saute for a minute. Add tomato. Saute again for a minute. Now, add turmeric powder, salt, freshly ground Sambar Powder.
Saute for 30 seconds and add in the soaked & drained dal, followed by sliced pumpkin. Add tamarind extract & water. Add some more salt if needed. Now, close the pot.
Cancel saute mode. Close the instant pot and cook the sambar for 10 minutes under high pressure on Pressure cook mode. Let pressure release naturally. Check for salt and some jaggery. Mix well. Garnish with coriander leaves. Serve.