Chicken dopiaza is a classic Indian curry and translates as double onions. The key to this curry is to cook the onions for a long time slowly until they are golden brown; that way the will give curry a sweet nutty flavour.
Heat some groundnut oil in a large frying pan; a couple of tablespoons should do it. Add the chopped or sliced onion and fry until golden brown over a low heat. When the onions are ready; probably about ten to fifteen minutes reduce the heat and add the garlic, ginger, garam masala, garlic, cayenne, ground coriander, whole cardamoms, salt and peppercorns, stirring to mix.
Now put the heat up to medium high
Add tomato puree and stir fry for about 5 mins making sure that it doesn’t burn the spices. Add chicken thighs and toss to coat with the spice mixture. Add enough water to cover, and add the chilli – put on lid and simmer for about 40 mins until the chicken is cooked. Add lemon juice and fresh coriander – check seasoning and serve with rice.