Duck stock, caramel-colored and intense, gives a savory depth to all sorts of dishes, including those in this month's story "The World of Duck." To tease out all the remaining meaty flavors from the carcass of roast duck or the legs left over when making a duck sugo, simmer the bones with plenty of aromatics. For a classic French-style duck stock, combine duck bones and any trimmings with roughly chopped onion, leek, celery, garlic, sprigs of parsley and thyme, a bay leaf, and a couple of whole cloves in a large stockpot. Cover with water and simmer, skimming often, until fragrant and slightly reduced, about two hours. Strain the stock through a fine-mesh sieve, discarding the solids. Cool completely and refrigerate or freeze until ready to use. The stock can be used to enhance the rustic flavors of cassoulet au canard (baked white bean and duck casserole) or, with additional aromatics, it can be transformed into the recipes below.