Nigella seeds, popularly known as Kalonji Seeds, are small, matte-black grains with a rough surface and an oily white interior. The seeds are frequently referred to as Black Cumin. They are seeds of a plant Nigella Sativa, of the buttercup family and are often confused with Onion Seeds and Black Sesame Seeds. This seed is used to flavor breads and pastries, it is a well known ingredient in English seed cake and is used in other desserts as well.