Rinse the chana dal under running water two to three times until the water runs mostly clear.

Soak the rinsed dal in fresh water for 30 minutes so it cooks evenly and turns soft in the cooker.

Drain the soaked dal, add it to the pressure cooker with turmeric, salt, and enough water to cover by an inch, and cook for 3-4 whistles until soft but still holding shape.

While the dal cooks, finely chop the onion and tomatoes and slit the green chilies.

Heat oil in a kadai over medium heat and add the cumin seeds and mustard seeds, letting them sizzle and pop for a few seconds.

Add the chopped onions and sauté, stirring frequently, until golden brown at the edges.

Stir in the ginger-garlic paste and slit green chilies and cook until the raw smell disappears.

Add the chopped tomatoes, turmeric, red chili powder, and coriander powder, and cook, mashing occasionally, until the oil visibly separates at the edges of the masala.

Add the cooked dal along with its water to the masala, stir in the garam masala, and simmer uncovered until the dal reaches a slightly thick, pourable consistency.

In a small pan, heat oil and fry the sliced garlic and dry red chilies until the garlic turns golden brown, then pour this tempering over the simmering dal.

Turn off the heat, sprinkle chopped coriander leaves over the dal, and let it rest briefly so the flavors settle before serving.