To truss a duck for roasting or braising whole, cut off the wings, leaving only the first bone. Tie string around the legs, then bring it around the thighs and between the breast, finally tying it under the front part of the breast.
Cutting up a raw duck will give you the two pieces of the breast for grilling or frying, the legs for braising or grilling, the fat for rendering, and the carcass and other pieces for making stock for soup or sauces. First remove the wishbone and slice down along the line of the breastbone to remove the two breast pieces. Then cut off the legs, including the piece called the oyster at the base of the thigh bone.
To make a stock for soup or sauces, prepare a mirepoix or cut up equal quantities of carrots, onions, and celery. Make an herb bouquet. For a brown stock roast the carcass and pieces in a 400° oven for 30 minutes and follow the instructions. To make a white stock do not roast the bones and follow the same procedure.
For a quick grill or sauté, or for meat for salads, pastas, and fast ragouts, the duck can be preroasted in order to render some of the fat out from under the skin. Cut the duck in half, salt the two pieces, and rub them with dried thyme. Leave the duck to marinate for 3 hours, then roast in a 400° oven, the breast for 15 minutes and the legs for 25. Remove the pieces, let cool on a rack, and bone.
To bone pieces of a half-cooked duck (the next step in the above process), cut around the wing bone and remove the skin, and cut off the ball joint. Remove the thigh bone from the leg piece and any extra fat under the skin. The pieces are now ready for further marination in herbs and oil for grilling, or just salt and pepper if sautéing.
Remove the skin from the legs or breasts (as you would for salads, pasta garnishes, or fast ragouts), put it on a rack and bake in a 350° oven until the fat is rendered and the skin is crisp. Cut it up to sprinkle on salads, pasta, omelets, or sandwiches. Take raw or half-cooked fat and put in a pan with 5 times its volume of water. Simmer until the fat is dissolved. Strain and skim off the fat, or place the pan in the refrigerator until the fat is solid. Remove and discard the water. The fat can be kept covered in the refrigerator for 2 weeks. Do not discard the bits of skin and fat membrane from the straining, but bake or fry them and use the same way that you would crisp skin, or salt the pieces and use for snacks.