Wash the dal and transfer it to a pressure cooker. Add 1.5 cups of water along with turmeric powder and pressure cook the dal for 4-5 whistles or until dal is completely cooked. Let the pressure release naturally.
To a mixer grinder, add all the ingredients listed under 'To grind' along with little water and grind to a smooth paste. Set aside.
Cut the shallots, tomatoes, green chilies and gather the rest of the ingredients required to make the sambar.
Once the pressure has settled, open the lid of the cooker and mash the dal.
In a kadai, add oil+ghee and let it heat. When it is hot, add the mustard seeds, cumin seeds, fenugreek seed, and whole pepper. Let it splutter.
Add the curry leaves and the green chilies and fry for a few seconds.
Add the shallots and saute them until the turn translucent.
Now, add the tomatoes and cook till they turn soft and mushy.
Add the sambar powder and mix well.
Add the ground paste and cook till the raw smell disappears.
Add the tamarind extract.
Add the red chili powder and the mashed dal and mix well.
Add 2 cups water along with the salt, mix well and let it come to a boil.
Add the tiffin sambar powder.
Let the sambar boil until it reaches the desired consistency. Now, add coriander leaves.
Finally add hing and switch off the stove.
In a tadka pan, heat ghee / oil.
Add the curry leaves and the red chilies. Let them fry for a few seconds.
Temper the sambar with the above tadka and serve with idli, dosa, pongal or vada.