Forget the sickly-sweet chicken kormas you may have had in the past. This is a rich curry with the hint of a kick but is in no way cloying. Adapted from the recipe for Fowl Quorema in The Indian Cookbook, 1880.
Heat 50 g / 2 oz / ¼ cup of the ghee or butter in a large saucepan or casserole. Fry the onion slices until crisp and brown. This will take a while so feel free to prepare the remaining ingredients while they are cooking. Remove with a slotted spoon and reserve until required.