Rinse 1 cup toor dal and soak for 20 to 30 minutes
Pressure cook the dal with 3 cups water, 1/2 teaspoon turmeric, and salt until soft
Mash the cooked dal lightly and set aside
Heat 2 tablespoons ghee or oil in a pan
Add 1 teaspoon cumin seeds and let them splutter
Add 1/2 teaspoon mustard seeds and 2 to 3 dried red chilies
Add 1 chopped onion and sauté until golden
Add 1 teaspoon ginger-garlic paste and cook for 1 minute
Add 1 chopped tomato and cook until soft
Add 1/2 teaspoon red chili powder, 1/2 teaspoon coriander powder, and a pinch of asafoetida
Add the cooked dal and mix well
Add water to adjust consistency and simmer for 5 to 10 minutes
Add chopped coriander leaves
Add lemon juice if desired
Serve hot with rice or roti