This prep has become my favorite, it is a combination of Asian and Italian style that imbues the duck with savory herbal flavors.
Purchase the duck two days before you plan to roast it. When you get it home remove the giblets (eat the lovely liver) and rub all over, inside and out with an Italian herb mix, dried herbs are perfect for this (and always in season.) Place duck in a plastic bag and add one cup good balsamic* vinegar and one cup dark soy sauce, along with a cup of star anise. Squeeze the air out and seal the bag and put in a pan or bowl. Refrigerate for 24 hours.
Remove duck from bag and place on rack and leave uncovered in the refrigerator for the skin to dry.
When ready to roast lightly salt the skin and cavity, hit with a grind of black pepper and place on a rack with a roasting pan containing some water underneath. Prick the skin all over and place in a 425 oven for 30 minutes. Lower oven to 250, but do NOT open the door. Roast for 3 hours. Check the skin, if further crisping is required up the oven temp until you get the brown you want.
Make sure you let it rest for about 20 minutes before carving.
The low temp allows much of the fat to melt and you will get a succulent tasty meat.
Though the flavors are Italian and Asian this duck is particularly good served with saurkraut.
*Much of what is sold as Balsamic is fake. Trader Joes' does not have one real balsamic. They take red wine vinegar and add color and flavor. The fake stuff may be passable in a salad but not in a dish like this. Look for REAL balsamic, if caramel color is added it is a fake.