For centuries, settlers in eastern Canada managed short growing seasons by relying on a simple technique to preserve tender herbs and onions: salting. Herbes salées (literally, salted herbs) traditionally was a mix of finely chopped onion greens and bulbs layered with salt and water. Other vegetables and herbs sometimes were added. The mixture—which steeped for several weeks, then could be kept for more than a year—was used to season soups, stews and meat pies. Chef Eric Cooper, of Forage restaurant in Cambridge, Massachusetts, makes his own using a wide variety of ingredients—including dill, chives and hyssop—then uses it to season soda breads, soups and roasted vegetables. Many companies sell herbes salées online. Our favorite is Les Herbes Salées du Bas-du-Fleuve, for its bright, briny salinity and rich vegetable flavors from a mix of celery, onions, carrots, parsnips, parsley, chervil, savory, leeks, chives and spinach. We like to mix it with softened butter to season steamed vegetables, or stir it into ricotta for a spread for crostini with fresh tomatoes. We also use it to season the cooking water for couscous and rice. Online retailer sells 250-milliliter jars for about $3.