Bay leaf is the aromatic, leathery leaf of the bay laurel (Laurus nobilis), a slow-growing Mediterranean evergreen tree whose stiff, glossy leaves carry a warm, cooling, eucalyptus-and-clove fragrance into stocks, braises and bouquet garni. Native to the eastern Mediterranean and Asia Minor, the same laurel that crowned Greek and Roman victors, it is used whole rather than eaten — a leaf or two dropped into a simmering pot, releasing its scent slowly over long cooking and then fished out before serving. Snapped fresh, the leaf smells sharp, green and almost medicinal; dried and aged, it mellows into the rounder, balsamic, faintly bitter warmth most cooks know. It is the quiet backbone of European braising — present in almost every long-cooked stock, soup, sauce and stew, yet rarely the flavour you can name.