Pressure cook or simmer the soaked chickpeas with water, tea bags, cinnamon stick, black cardamom, and half the salt until tender.
Discard the tea bags and set aside the cooked chickpeas in their dark soaking liquid.
Heat oil in a heavy-bottomed pot over medium heat and add cumin seeds until they sizzle.
Add the chopped onions and sauté until they reach a deep golden brown color.
Stir in the ginger-garlic paste and green chilies, sautéing for 2 minutes until the raw aroma dissipates.
Add the tomato puree and cook until the oil starts to separate from the spice base.
Stir in the chana masala blend, coriander powder, turmeric, and red chili powder.
Pour in the chickpeas and their dark cooking liquid, stirring well to combine with the masala base.
Add the amchur powder and remaining salt, then simmer on low heat for 15 to 20 minutes until the gravy is thick and flavorful.
Lightly crush a few chickpeas with the back of a spoon to further thicken the sauce.
Garnish with fresh cilantro before serving.