Ingredients

• 1 (2-inch) piece ginger, peeled
• 3/4 lb Shanghai bok choy or other baby bok choy (5 to 8 heads)
• 1/4 cup reduced-sodium chicken broth
• 1 teaspoon Chinese rice wine (preferably Shaoxing) or medium-dry Sherry
• 1 teaspoon soy sauce
• 1/2 teaspoon cornstarch
• 1/2 teaspoon salt
• 1/4 teaspoon sugar
• 1 tablespoon vegetable oil
• 1/2 teaspoon Asian sesame oil
• Special equipment: a rasp grater; a well-seasoned 14-inch flat-bottomed wok
• Accompaniment: steamed white rice

Instructions

1. Cut half of ginger into very fine matchsticks (less than 1/8 inch thick; about 1 tablespoon) and reserve. Grate remaining ginger and squeeze pulp with your fingers to yield 1 teaspoon liquid, then discard pulp.
2. Remove any bruised or withered outer leaves from bok choy. Trim 1/8 inch from bottom of each bok choy, then cut each head into quarters. Wash bok choy in several changes of cold water and dry in a colander or salad spinner until dry to the touch.
3. Whisk together ginger juice, chicken broth, rice wine, soy sauce, cornstarch, salt, and sugar in a small bowl until cornstarch is dissolved.
4. Heat wok over high heat until a bead of water vaporizes within 1 to 2 seconds of contact. Pour oil down side of wok, then swirl oil, tilting wok to coat sides. Add ginger matchsticks and stir-fry 5 seconds. Add bok choy and stir-fry until leaves are bright green and just limp, 1 to 2 minutes. Stir broth mixture, then pour into wok and stir-fry until vegetables are crisp-tender and sauce is slightly thickened, about 1 minute. Remove from heat and drizzle with sesame oil, then stir to coat.