Ken Hom's garlic chicken

Cut the ginger into slices 7.5cm x 5mm (3 x ¼ inch) and cut the spring onions into 7.5cm (3") pieces. Rub the chicken with salt and stuff the cavity with the ginger and spring onions. Let it sit at room temperature for 30 mins. Next, set up a steamer or put a rack into a wok or deep pan and fill it with 5cm (2") of water. Bring the water to the boil over a high heat. Put the chicken on to a heatproof plate and then carefully lower it into the steamer or onto the rack. Turn the heat to low and cover the wok or pan tightly. Steam gently for 1 hr or until the chicken is cooked through to the bone. Top up with boiling water from time to time. Place the chicken on a rack over a tray or roasting pan and leave in a cool, well-ventilated place to dry for about 3 hrs. (To speed up the process, place it in front of a fan for 2 hrs.) When the chicken has dried, the skin should feel like parchment paper. Cut it in half lengthways, then wipe the cavity dry with kitchen paper. Mix together the sauce ingredients and set aside. Heat a wok or deep frying pan until it is very hot. Add the oil and when it is hot and slightly smoking, deep-fry one half until it is golden and crisp. Remove and then do the other half. Drain on kitchen paper. When it is cool enough, cut into bite-sized pieces. Place on a warm platter and pour the sauce over. Serve at once.