Take a stockpot sized pot and put it on medium high heat, wait a few minutes, and then add the oil. When the oil is hot then add in the onions and the cumin seeds & cook until the onions start to turn golden brown at the edges.
Add the garlic and ginger pastes and stir for another minute or two, then add the salt, chilli powder, turmeric powder, and coriander powder and let it cook until it becomes a cohesive paste, be careful not to burn it. If it starts to stick then add a tablespoon of water.
Now add the chopped tomatoes and cook till soft.
Add the chicken pieces into the pot, stirring to ensure that the chicken turns white on all sides.
Now in goes a cup of hot water, the chickpeas, and a pinch of baking soda, bring it to a boil, and then let it cook covered on low heat for another 25-30 minutes.
Uncover your pot, check the chicken for doneness, it should be nice and tender
Adjust the consistency of your gravy by adding water then add the garam masala, the black pepper, the green chillies and cilantro. Cook for 2 minutes then taste and adjust seasoning.
Garnish with additional cilantro and green chillies if desired and serve hot.