1. Preheat the oven to 425°. Wash the duck under cold running water and pat dry inside and out with paper towels. Rub the inside of the duck liberally with salt and pepper. For crisper skin, prick the surface around the thighs, the back, and the lower part of the breast with the tip of a sharp knife.
2. In a large bowl, combine the beef, pork, egg, crumbs, marjoram, 1 teaspoon of salt and a few grindings of pepper. Knead vigorously with both hands until the ingredients are well blended and the mixture is smooth. Then stir in the apples and spoon the stuffing loosely into the cavity. Close the opening by lacing it with skewers or sewing it with heavy thread. Fasten the neck skin to the back of the duck with a skewer and truss the bird securely.
3. Roast the duck, breast side up on a rack set in a large shallow pan, for 20 minutes, until it browns lightly. Pour off the fat from the roasting pan or draw it off with a bulb baster. Then reduce the heat to 350°, and roast for about 1 hour longer, removing the accumulated fat from the pan occasionally with a bulb baster.
4. To test for doneness, pierce the thigh of the bird with the tip of a small, sharp knife. The juice should spurt out a clear yellow; if it is slightly pink, roast the bird for another 5 to 10 minutes. Transfer the duck to a heated platter and let it rest for 10 minutes before carving. Traditionally the duck is accompanied by red cabbage and dumplings.
