"An experienced saucier uses herbs at several stages of the sauce-making process," writes author James Peterson in his seminal book Sauces: Classical and Contemporary Sauce Making. A bouquet garni—a neatly tied bundle of parsley, thyme, and bay leaf—adds a layer of herbaceous flavor to stocks, the first stage of preparing a sauce. Usually made by tying together herbs with kitchen twine or enclosing them in cheesecloth; at Le Ferrandi, the famed cooking school in Paris, students take a more resourceful approach. Using items that are usually thrown away—namely the tough outer leaves of leeks—to encase fresh sprigs of flat-leaf parsley, thyme and other aromatics.