Cut the leafy portion of mustard green off, and then cut the green stem into approximately 1.5-inch square pieces. Use fresh or refrigerated cooked crabmeat if available. Otherwise canned crabmeat can be substituted.

Heat two tablespoons vegetable oil in a wok until beginning to smoke. Put the mustard green in the wok and add 1/2 cup of stock or water. Cover the wok and simmer over medium heat for about 8 minutes. Stir the vegetable occasionally to make sure it is evenly cooked. When the vegetable is cooked and tender, but not mushy, remove it from the wok along with all the liquid and put it in a bowl. Set aside.

Heat another one tablespoon of vegetable oil in the wok and stir-fry the garlic and ginger for about a minute. Add the crabmeat, cooking wine, salt, pepper and the rest of the stock or water. Cook for another two minutes or so and return the vegetable and its liquid into the wok. Thicken the sauce with the cornstarch slurry. Plate and serve immediately. To make it even more elegant garnish the dish with a sprinkle of cooked crab roe.