This recipe follows the Punjabi chana masala style: a tomato-onion masala cooked down until the oil separates, then given a tangy lift with amchur at the end of cooking. Amchur (dried green mango powder) provides the dish's signature sour note. If you don't have any, replace it with a teaspoon of lemon juice added off the heat, or with ground anardana (dried pomegranate seeds).Dried chickpeas are the real foundation of this curry: soaking them overnight and then cooking them gives them a firm texture and a flavor that canned chickpeas can't match. For a quick version, replace them with 2 cans of chickpeas (2 x 400 g, or about 480 g drained): skip the soaking and cooking, rinse them, and add them straight to the masala. The curry is then ready in around 30 minutes instead of roughly 1 1/2 hours, not counting the overnight soak.The black cardamom, green cardamom, and cinnamon stick flavor the oil but aren't meant to be eaten: warn your guests or remove them before serving. The baking soda isn't essential, but it softens the dried chickpeas and shortens their cooking time.