Step 1

Preheat oven to 160°C. Combine the plum and soy sauces, sesame oil, garlic, Chinese five spice and star anise in a small bowl.

Step 2

Combine the boiling water and crumbled stock cubes in a jug. Pour the stock mixture into a large roasting pan. Place a wire rack over the top of the pan and place the duck, breast-side up, on the wire rack.

Step 3

Place garlic cloves and ginger into cavity of the duck. Tie legs loosely together with unwaxed white string. Brush duck with half of the sauce mixture. Cover tightly with foil and bake in preheated oven for 1 1/2 hours. Turn duck over and bake, covered, for a further 1 1/2 hours.

Step 4

Increase oven temperature to 190°C. Brush duck with remaining plum mixture and season with salt and pepper. Roast, uncovered, for a further 20 minutes or until brown and juices run clear when the thickest part of the thigh is pierced with a skewer. Remove from oven and cover with foil. Set aside for 10 minutes to rest.

Step 5

While duck is resting, tie white unwaxed string around the stems of each bunch of choy sum to secure. Add to a large saucepan of salted boiling water and cook, uncovered, for 1-2 minutes or until bright green and leaves just wilt. Drain well. Place on a clean work surface, remove the string and use kitchen scissors to cut each bunch into 3 equal lengths. Place in a large bowl with the extra soy sauce and toss to combine.

Step 6

Use poultry shears to cut along either side of the duck backbone then discard backbone. Cut duck in half lengthways then cut each half into 3 pieces. Serve immediately with choy sum and top with green shallots.