Cut the crabs into 2 pieces and separate
the legs and claws. Heat up a wok with the oil and fry the crab pieces
until reddish. Remove and drain. Toss in the finely chopped
onions and ginger root in what is left of the oil in the wok. Add soy sauce, sugar, rice
wine or sherry and vinegar. Thicken with cornstarch
mixed with a little cold water. Then return the crab
pieces to be coated by this sauce. Blend well and serve while hot.