To prepare Kala Chana, there is overnight prep involved to rehydrate the brown chickpeas. Soak the brown chickpeas overnight (or minimum 8 hours) in plenty of water with a pinch of baking soda. They will swell up to almost 3 times their original size. Drain and keep aside.

Place the drained brown chickpeas in a pressure cooker and cover with 4 cups of water with a pinch of baking soda and asafoetida. After 4 whistles, keep the flame on sim (lowest setting) for around 10 minutes and turn off the flame. Open cooker when it has cooled.

In a heavy bottom cast iron pan / kadai (Don't use non-stick pan here if you want the best results) - heat a tbsp of oil. Throw in the black cardamom and shah jeera. After 30 seconds, put in the ginger garlic paste and saute till golden in colour. Now add in the finely chopped onions.

Now comes the call for patience. Keep the flame between medium-high. Let the onions get brown and as they just start sticking to the bottom, add a few tsp of water to 'deglaze' the pan or loosen up the burnt bits. Let the flame be on medium high and keep repeating this procedure of letting the water evaporate, onions starting to stick to the pan and deglazing with water some 5-6 times. You would be using roughly 1/2 cup of water during the entire process which will take upto 20 minutes.

The result of this process will be blackish brown caramelized onions, turned extremely soft and superbly RICH in flavour - both from its own caramelization and infusing the flavours of the spices used. Using a non-stick pan will not give you the depth of flavour that is the cornerstone of this recipe.

By this time, the chana in the cooker would have cooled off. Open the cooker lid and check if the Chana are cooked to a soft consistency. They should crush easily between your thumb and index finger with a slight pressure. Black chickpeas are quite thick skinned so they will never cook to a mush, which is why you can safely overcook them in a pressure cooker without expecting a slush in the end.

Drain the cooked chana. Reserve the liquid. Add the cooked chana to the onions. Also put in the slit green chillies and salt. Keep the flame on medium high and let the chickpeas cook some more with the onion mix. Add the reserved liquid little by little if you find the curry going too dry. In all, let them all simmer together happily for some 15 minutes. If by chance the chickpeas were old and they didn't succumb to pressure cooking, you can do one more round of the whole curry in the cooker for around 5 minutes.

Remove from flame. Garnish with some fresh coriander. Serve with freshly made hot puris.