You need to be a bitter green fan to enjoy this dish. Or at least enjoy strongly flavored greens. We served this braised gai choy with some leftover lechon, presumably to help temper the evils of cholesterol overload, and it worked flavorwise. But I can see how this would also be a rather tasty vegetarian dish on its own.
First soak/wash the mustard cabbage leaves thoroughly. You need to separate them before washing so that any residual sand/soil is easier to remove. Then cut out the tougher central stem/rib that is almost as crisp as celery. Next chop these up into 1/2 inch pieces and set these aside. Next, chop up the leaves and place them in a separate bowl.
Chop up several cloves of garlic. Prepare 1/2 – 1 cup of chicken stock (use vegetable stock if you want this to be a vegetarian dish), some kikkoman soy sauce, pepper, salt and olive oil.
Heat up a large wok, add some olive or vegetable oil, the garlic and saute for a few seconds over medium high heat. Next add the sliced stems of the gai choy and saute for about 1 minute or so. Add 1/2 cup of chicken stock and let the stems braise over medium high heat until slightly softened, say 5 minutes for young gai choy, longer for older and larger gai choy. Add some water if the liquid seems to be evaporating too quickly.
Next add the chopped leaves and stir well. Ad a tablespoon or two of kikkoman soy sauce. Add a bit more broth if necessary and braise for say another 5 or so minutes until the stems are relatively soft and the greens are cooked as well. Add some freshly ground black pepper.
Serve hot. It is a bit bitter and garlicky. Some folks would love this dish, others would probably dislike it just as intensely. :)