These black seeds are sometimes called black cumin or onion seeds. They have a slightly bitter, oregano herb-like taste and provide a brilliant crunchy texture. Nigella seeds are used extensively in Indian and Middle Eastern cooking, adding flavour to curries, pulses, stews, breads, salads, pickles and chutneys. The seeds are bought whole and can be used without dry roasting, although this will enhance the flavour. They will last about year in a dry, airtight container, which is kept out of direct sunlight.