I've not yet experienced black cumin, so it's another spice I look forward to trying.
Black cumin plants
Black cumin fruits (often incorrectly named "black cumin seeds"
Ground black cumin
The plant is found wild from Central Asia to North India. There is considerable confusion about this spice, particularly in older literature. It is sometimes incorrectly referred to botanically as carum bulbocastanum or cuminum nigrum.
Fruits. Both the dark brown colour and the slender crescent shape are characteristic. In Kashmir the root is eaten as a vegetable.
Apiaceae (parsley family).
The aroma of the raw fruits is earthy and heavy and not at all pleasant. On frying or roasting the taste changes and becomes nutty.
For the etymology of black cumin, see cumin. The derivation of Latin genus name bunium is uncertain, but it may derive from Sanskrit vnija "merchant" via the Hindi baniyā. Species name persicum is Latin for "Persian", a reference to the supposed origin of the plant. The modern Hindi Shahi jeera "Imperial cumin" refers to the popularity of black cumin in the Mogul cuisine of North India.
Similar names in Arabic refer to a quite different spice, ajwain. Kashmir is the only region in India where black cumin is grown and the name Kashmiri jeera refers to the plant from this region where the Mogul Emperors spent their summers to escape the heat of the Indian plains. A similar derivation applies to the Nepali Himali jira "Himalayan cumin". The most common Indic name for this spice is kala jeera "black cumin", a name sometimes given to the entirely unrelated spice nigella which is popular in the Middle East and Bengal.
Black cumin (in India also called Kashmiri cumin) is not much known outside Iran, Tajikistan, Afghanistan, Pakistan and the Western part of North India (Kashmir and Punjab). It is preferred to ordinary cumin for some Indian meat dishes (kormas) and rice dishes (biryanis) but if unavailable, toasted cumin is an acceptable alternative.
North Indian sauces and gravies are usually based on onion, garlic and fresh ginger as in the rest of India. Cinnamon, cloves, black cardamoms and green cardamoms are fried in hot ghee (clarified butter fat) until they darken and begin to release their fragrance. With the heat reduced, onion, garlic, ginger and Indian bay leaves are added and fried until the spices turn light brown. After the mixture has been quenched with yoghurt and black cumin, the spices fennel and paprika are added and meat or vegetables are cooked in the gravy until tender. The sauce may be thickened with ground poppy seed or grated almond.
Food prepared in this way, by braising in a previously spiced sauce, is referred to as korma. The term korma is of Persian origin and Iranian ghorme is a thick sauce made of herbs and vegetables used as a base for long-simmered stews.