Rau Muong is the Vietnamese name of ipomoea aquatic, a staple leafy green vegetable that grows all over Asia in tropical and subtropical regions. It grows quickly and plentifully in moist environments, in moist soil or shallow water, and is therefore cheap and widely available. It’s known by seemingly a whole host of names, including water spinach, swamp cabbage, Chinese spinach, kongkang, water convolvulus (whatever the hell that means), morning glory, ong choy, phak bung, and “hollow vegetable” which is a transliteration of a (to me) unpronounceable Chinese word.
Very healthy and quite mild, rau muong is a snap to cook and worth the trouble of finding. In the US you should be able to get them in most good Asian grocery stores, especially in areas of concentrated Southeast Asian populations like here in Los Angeles. If you can get your hands on the stuff, first trim off any woody or dried-out stems. Also, discard any unwholesome-looking leaves. Cut the veggies into lengths about two-to-three inches and rinse well.
When my mother cooks it she blanches the rau muong for about three minutes in salted boiling water until slightly tender and then she rinses it in cold water to halt the cooking process. She allows it to drain until dry and then heats up a wok until very hot. She swirls in a little vegetable or peanut oil to coat the bottom of the wok and then adds the greens. As they soften she’ll add about six cloves of minced garlic (starting with about two pounds of cleaned greens) and season with salt, pepper, a bit of sugar, and a little MSG. Naturally the MSG isn’t mandatory, but a tiny bit will go a long way and it kicks up the flavor quite nicely. When she adds the spices she’ll put, say, about a teaspoon-and-a-half of salt, a half-teaspoon of pepper, a half-teaspoon of sugar, and a quarter-teaspoon of MSG in a quarter-cup of warm water. She pours the seasoned water over the veggies and tosses the whole thing with big cooking chopsticks to evenly distribute.
The stir-frying part of the cooking process is only about five minutes. So in no time you’ll have an amazing, healthy side dish to go along with all kinds of fish, poultry, meats, and rice.
When I’ve cooked the stuff I like to add fiery chillies, a splash of fish sauce or soy sauce, sometimes shallots or scallions. Sometimes ponzu or toasted sesame oil. Add whatever you like. Rau Muong is versatile. And yummy.