Wash the toor dal thoroughly and cook it with 2 cups of water in a pressure cooker until it's soft and mushy.
In a separate pot, extract tamarind juice by squeezing the soaked tamarind in water. Discard the pulp.
Add the chopped tomato, turmeric powder, and salt to the tamarind juice. Cook until the tomato turns soft and pulpy.
Now, add the cooked toor dal to the tamarind-tomato mixture and let it simmer.
In a separate pan, heat oil or ghee. Add mustard seeds and let them splutter. Add cumin seeds, dried red chilies, asafoetida, curry leaves, and minced garlic. Sauté until fragrant.
Pour this tempering over the simmering dal-tamarind mixture.
Add red chili powder for a spicy kick (adjust according to your preference) and let the Pappu Charu simmer for a few more minutes.