Kashmiri butter chicken

Method

1. Make the Kashmiri garam masala. Heat a dry, heavy-based frying pan over a high heat. Lower the heat to medium, add all the spices but the nutmeg and shake the spices around in the pan for a few seconds until they darken slightly and start to smell aromatic. Tip into a spice grinder or a mortar and grind to a fine powder. Stir in the nutmeg. (Any leftover garam masala will keep, sealed, in a small glass jar, for up to 2 months.)
2. Put the onion, garlic, grated ginger, lemon juice, chilli powder if using, paprika, 1 teaspoon of the garam masala and 1 tablespoon oil into a small food processor and blend to a smooth paste, adding a tablespoon or 2 of water, if necessary.
3. Heat the remaining oil in a large, deep frying pan or flameproof casserole, add the chicken pieces and fry them over a medium-high heat until lightly browned on both sides. Remove to a plate and set aside. Add the butter and spice paste to the pan and fry for 3-4 minutes until the paste starts to separate from the oil. Add the tomato purée mixed with 250ml water, the salt and sugar. Cover and simmer for 10 minutes.
4. Stir the shredded ginger and cream into the sauce, then add the chicken pieces, turning them once or twice to cover them in the sauce. Cover and simmer for 15-20 minutes, stirring now and then, until the chicken is tender and cooked through. Uncover, sprinkle with the remaining garam masala and the chopped coriander and serve with naan bread or basmati rice.