Rinse the toor dal well and soak it in water for 30 minutes.
In a pressure cooker, add the soaked dal, 4 cups of water, turmeric powder, and salt. Cook for 3-4 whistles or until the dal is soft.
Once the pressure releases, mash the dal slightly and add tamarind pulp. Mix well and simmer for 5-7 minutes.
In a separate pan, heat ghee or oil. Add mustard seeds, cumin seeds, dried red chilies, and curry leaves. Let them splutter.
Add chopped onions and sauté until golden brown. Add ginger garlic paste and sauté for another minute.
Add chopped tomatoes, red chili powder, and coriander powder. Cook until the tomatoes are soft and the oil separates.
Add this tempering to the simmering dal. Mix well and cook for another 5 minutes.
Garnish with fresh coriander leaves and serve hot with rice or roti.