Rub the duck inside and out with salt, pepper and marjoram. Chill overnight in the fridge.
The next day, preheat the oven to 180 C / Gas 4.
In a bowl, combine all ingredients for the stuffing. Fill the duck and secure with kitchen string or skewers.
Place the duck in a roasting tin, then pour in 350ml water and cover.
Roast for 2 to 3 hours, depending on the size of the duck (one hour for every kg). Cook until the meat is tender and the juices run clear (remove the cover for the last 15 to 20 minutes to allow the skin to get golden). Remove from the oven and serve.