Most commonly found in the form of whole, dried leaves, bay leaves (also called laurel leaves) bring an aromatic, woodsy note to a dish. Common in slow-simmering dishes, such as soups and stews, they should be added to the dish whole (never crumbled). Also discard them before serving the dish. There are two varieties. Turkish (1 to 2 inches long oval) and California (2 to 3 inches long narrow) and can be used interchangeably. The Turkish is said to have the better flavor.
Fresh bay leaves are rarely available but dried leaves can be stored up to 6 months in a cool dark place.
If you need to substitute you can use 1/4 tsp. of thyme in place of 1 whole bay leaf.