Combine ingredients (A) together and rub the mixture over the duck skin. Place star anise and garlic with the remaining mixture into the duck cavity. Sew up the cavity to prevent the sauce running out.
Bring water to a rapid boil then place the duck on a rack over the sink. Scoop hot boiling water over to bathe the duck.
Pat dry the duck with several layers of kitchen paper towels.
Combine ingredients (B) in a saucepan to heat up the mixture. Dip a brush into the mixture and brush it over the duck.
Hang the duck to air-dry for at least 3 hours.
Preheat oven at 175°C then roast the duck for about 20 minutes. Turn over every 5 minutes.
Reduce the heat to 150°C and continue to roast for 20 minutes. Reduce the temperature to 125°C and continue to roast for 10 minutes. In the final round of roasting, bring up the heat to 200°C then roast for 8-10 minutes until the skin is golden brown. Remove duck from the oven and leave aside to cool before cutting.