Briefly wash the gutted duck and season inside and out with salt and ground pepper. Place the marjoram sprig and oranges or apples in the abdominal cavity and close the opening with a roulade skewer. Cut particularly fat ducks crosswise on the breast with a sharp knife, but only cut into the fat, not the meat. In a large roasting pan or skillet, sear the duck well in hot oil, first on both sides of the breast and then on the thighs and back. Roast on a rack or fat grid in a preheated oven at about 150 °C for 1.5-2 hours. Place a deep baking tray with some water underneath. Shortly before the end of cooking, brush the duck with a little honey and very little good balsamic vinegar or apple balsamic vinegar and roast at a higher temperature (200°C) until nice and crispy. Lift out and carve at the table, if desired.