In a small mixing bowl, mix all marinade ingredients together.
Make sure to clear the duck’s cavity before stuffing with ⅔ marinade mixture. Enclose the cavity with thick thread or a bamboo/stainless skewer. Rub the left over marinade mixture all over the outside of the duck.
OR cut the duck in half and rub the marinade mixture all over 2 halves.
Let it marinade for at least 2 hours, maximum 6 hours in a chiller, breast side up.
After 2 or 6 hours, rinse whole duck (with cavity still enclosed) or half duck under cold tap water. Mean while, bring a medium pot of water to boil.
Secure the duck with a hook or use anything that you can actually carry the duck in one hand. While using other hand to ladle the hot boiling water all over the duck skin. Make sure to cover all parts of the duck with hot boiling mixture, especially the breast. (DO NOT submerge the duck under hot boiling water).
Hang the duck or place it on a sheet pan, breast side up in a chiller, uncover. Let it sit for at least 24 hours, maximum 48 hours.
Pre-heat oven 380F/195C. Put the duck on roasting rack, breast side up. And roast for 15 minutes. After this, use aluminum foil and cover the wings part and legs joints to prevent them from burning.
Turn the heat down to 300F/150C. Cook whole duck for another 30 minutes OR half duck for 20 minutes.
When the duck is done cooking, take it out of the oven and let it cool down for 10-15 minutes. Take out the stuffing inside duck's cavity if you cook whole duck. Then proceed to cut the duck into pieces.