There is a lot of confusion about the name of this spice. Nigella seeds are also known as kalonji, black cumin, black caraway or black onion seeds. They are the tiny, tear-drop shaped seeds of a small plant whose beautiful flowers have been known for a long time as Love-In-A-Mist. To make matters worse the seeds are sometimes confused with black sesame seeds which have a similar size and color. In an effort to clear up some of the confusion, let me point out that there really is a black cumin seed (kala jeera) and some onion seeds are very similar, but they are not nigella seeds and would not taste the same in a dish. True onion seeds tend to have little, if any, flavor and the flavor that they do have tends to be rather unpleasant.
Nigella’s main application area is Turkey, Lebanon and Iran. From Iran, nigella usage spread to Northern India, particularly Punjab and Bengal, where the spice is mostly used for vegetable dishes. Their dusty jet black color and earthy, distinct onion flavor is an essential part of Panch Phoran (Indian Five Spice), a Bengali spice mixture
The black seeds taste mostly like oregano crossed with pepper. Most people use it as a “pepper” in recipes with pod fruit, vegetables, salads and poultry. Because of nigella seeds crunchy texture, it is sprinkled over soft tandoor-baked breads, such as naan, as is done in Northern India. While the seeds are used as a spice in Indian and Middle Eastern cuisine, in the Balkan region it is sometimes used with or instead of peppercorns in a pepper mill.
Its therapeutic powers include: cleansing of toxins in the blood, helping to stimulate the liver, and used as a paste to clear skin blemishes.