Rinse the urad dal thoroughly under cold water until the water runs clear.

In a large pot, combine the rinsed urad dal with water and cook over medium heat until tender, approximately 30 minutes. Stir occasionally to prevent sticking.

In another large pot, heat safflower oil over medium heat. Add black mustard seeds, cumin seeds, and curry leaves. Sauté until the seeds start to crackle.

Reduce the heat to low. Stir in chopped cilantro, garlic or cayenne, and hing. Cook until the garlic turns slightly brown.

Once the tempering is ready, add the cooked urad dal along with any remaining water to the pot.

Sprinkle turmeric and salt into the soup. Stir well to combine all the ingredients evenly.

Increase the heat to medium-high and bring the soup to a gentle boil.

Once the soup reaches a boil, turn off the heat. Serve hot with rice or chapatis.