The Chinese technique of velveting meat is an oft-used yet underappreciated one. It refers to the coating of meat pieces in cornstarch, egg whites, wine, and other seasonings such as garlic and soy sauce, to make it more tender.
Learning how to velvet meat is as integral to Chinese cooking as say, browning meat is for the French or Italian. Meat that is stir-fried, boiled, or steamed without the protective layer of cornstarch could still be tender, but not nearly as silky as meat that's been velveted. More likely than not, the meat that you're eating at a Chinese restaurant has been velveted prior to being deep-fried, stir-fried, or steamed.
The basic ingredients when velveting are cornstarch, rice wine, egg whites, salt, sugar, and a bit of water to loosen the mixture. Beyond that, different recipes and cooks will call for additional items, such as minced garlic. Here are two recipes that use velveted meat.
The first is a straightforward pork and vegetable stir-fry where slivers of pork are velveted and sauteed with bamboo shoots, shitake mushrooms, and napa cabbage. It's a classic, simple, quick preparation—one of those dishes that would have come out of my mother's kitchen. The meat remains soft and tender. (You've probably noticed in Cantonese restaurants that stir-fried meat is almost never browned or seared.)
The second recipe is a spicy Sichuanese stir-fry: cubes of velveted chicken are "passed through" the oil, which means it's deep-fried in a shallow oil pool before stir-fried with the other ingredients. The deep-frying element makes this something you might find more at a Sichuan joint than a home kitchen, but it's an excellent example of the technique's versatility. The cornstarch coating makes the chicken crispy, and the meat inside juicy and tender.