Soak the toor dal for 20 minutes.

Drain and rinse it under cold running water.

Pick through the dal to ensure it has no pebbles or foreign contaminants hidden amongst it.

Place all of the toor dal, tomato, green chili, turmeric, Kashmiri chili powder, ginger, garlic, cinnamon, dried chilies, lemon juice, water (or broth), cilantro, and salt into a pot or pressure cooker.

If using a pressure cooker, close the lid of the pressure cooker and cook the dal over high heat until the pressure builds up and the steam starts to escape from the vent. Put on the stopcock, reduce the heat to medium-low, and cook for 15 minutes until the dal is soft and cooked through. Turn off the heat and let the pressure release naturally.

If using a pot, bring the contents of the pot up to a boil over a high flame.  Cover the pot and cook the dal on a low flame for 40 minutes until soft and cooked through.

If you want a soupier consistency, mix in a little additional water.

While the dal cooks, prepare the tadka by heating the oil in a separate saucepan over a medium flame.  After 90 seconds when the oil is hot, add the mustard seeds, coriander, and cumin seeds.

After 30 seconds, when the mustard seeds are rapidly popping, stir in the remaining ingredients and lower the flame to a simmer.  Cook the tadka for 10 minutes until the onions are fragrant and lightly golden.

To serve the arhar dal, place it into an attractive serving dish, and top it with the tadka. Garnish with fresh cilantro leaves.