Preheat your oven to 400°F (200°C) and line a roasting pan with aluminum foil, filling it with ½ inch of water or 2 cups of coarse salt.

Rinse the whole duck under cold water, remove excess fat and neck, and pat dry. Place the duck on a rack in the roasting pan, breast side up.

Mix the hoisin sauce, soy sauce, brown sugar, and Chinese five-spice powder. Rub this marinade on the duck and stuff the cavity with ginger, scallions, star anise, and a cinnamon stick.

Refrigerate the duck uncovered for 24-72 hours to air-dry, rotating every 8-12 hours. Let sit at room temperature for 1 hour before roasting.

Prepare the glaze by mixing maltose, coarse kosher salt, rice wine vinegar, and water. Brush this mixture over the duck.

Roast the duck for 40 minutes at 400°F (200°C). Check halfway and cover wings with foil if browning too quickly.

Carefully flip the duck, reduce temperature to 350°F (175°C), and roast for an additional 40-50 minutes until internal temperatures reach 160°F at the thigh and 145°F at the breast.

Remove the duck and let it rest for 15 minutes before carving and serving with steamed rice and stir-fried vegetables.