Completely defrost the duck in the refrigerator for 1-2 days, if using frozen. Once defrosted, rinse and pat dry. For best results, let the duck sit uncovered in the refrigerator overnight. This will help to dry and crisp the skin.
Use a sharp knife to score the skin on the duck’s breast in a diamond pattern, trying to cut only the skin without reaching the breast meat below. Cut off excess fat and poke the bird all over with a knife. Only prick the skin, don’t hit the meat.
Season the duck all over with salt, including the cavity. Stuff the cavity with garlic, shallots, lemon, apple and prunes. Use 2-3 toothpicks to sew the skin around the cavity opening tightly together, to keep the inside moist during roasting. Cross the legs and tie them together with a cooking twine. Fold the wings under the duck.
Place the bird on the roasting pan and cook at 148 degrees C for 1 hour, breast side up. After 1 hour, remove the bird and prick the skin all over again. Flip the duck breast side down and roast for another hour. Continue doing this process of poking and flipping the bird every hour for 3 hours.
Prepare the glaze by combining the glaze ingredients in a medium pan. Simmer until thickens, about 10 minutes. Remove from heat and set aside.
After 3 hours, remove the duck from the oven, poke once more, turn up heat to 204 degrees C and blast for 15 minutes, breast side up. Then brush with glaze and finish for another 5-7 minutes.
