Heat oil in pan
Then put hing and add chopped green chillies with onion and saute for 2 minutes
After that add chopped garlic and cook it till onion turns light brown in color
Now add turmeric powder, red chilli powder, garam masala, sambar masala and mix it well
After cooking the spices for 5 minutes add pumpkin, daal,tomato and salt and allow it to cook for few more minutes
When the mixture is half done, then transfer the mixture from pan to pressure cooker
After transferring the mixture, add 3 cups of water or as per your desired thickness of sambar and cook it till 3 whistles
Now switch off the flame, open the cooker and mix tamarind water in sambar
You can increase or decrease the quantity as desired
For Tadka:Heat oil in pan or tadka pan
Now add dry red chillies, curry leaves and rai
Wait till rai splutters and curry leaves becomes light crisp
Then immediately pour this tadka on sambar and mix it well
Now garnish sambar with coriandar leaves and your sambar is ready to be served with dosa, uttapam or idli
