The Hong Kong is no longer. But take heart, The Modern Art of Chinese Cooking by Barbara Tropp has a recipe for it called "Birthday Duck.’ It is much like the recipe above with a few extra ingredients and fillips. The skin stays on and the water chestnut powder is reduced accordingly. It has almonds and a wonderfully retro Am-Chi style pineapple sauce to go with. It’s worth tracking down; it’s not difficult, just labor-intensive.