Pressure cook the soaked black chana until soft. Retain the cooking water, which will have a rich, dark color. Strain the chana and set aside the cooked water for the soup base.
Heat oil in the same pressure cooker.
Add finely chopped garlic and sauté until golden brown and fragrant.
Stir in chopped coriander, cumin powder, pepper powder, turmeric powder, asafoetida, and salt. Sauté for 1–2 minutes until aromatic.
Pour in the reserved chana-cooked water and plain water. Stir well to combine.
Bring the mixture to a rolling boil.
Switch off the heat and serve the soup hot. Garnish with a sprig of fresh coriander if desired.