1. Dissolve the sugar in a little water and brush over the duck. Make small slits in the duck skin and loosen it slightly. Using a straw blow air under the skin.
2. Peel and dice the shallots and use to stuff the duck. Sew up the opening with cooking thread and truss. Hang the duck in a well ventilated place for about 12 hours, until the skin dries out.
3. Place the duck on a roasting rack over a roasting tin and roast in a moderate oven (180°C, 350°F, gas 4) for about 1 hour, turning it over after 30 minutes. After 45 minutes, increase the heat to hot (220°C, 425°F, gas 7) and brown the duck well for a further 10-20 minutes.
4. Mix the flour and salt to taste with the 6 tablespoons of hot water to make a dough. Roll out the dough to a thickness of 5 mm (1/4 in) and cut it into large rounds.
5. Lightly fry the pancakes on one side in a little oil until half cooked, then arrange them on a plate and steam over boiling water for 10 minutes. Trim, wash and finely slice the leeks.
6. Cut the cooked duck into small pieces. Arrange the meat and crisp skin on a plate. Serve the thinly sliced leeks separately with the pancakes and soy sauce.