In wok or large sauté pan over moderately high heat, heat oil until hot but not smoking. Add ginger, scallions, and garlic and stir-fry until aromatic, about 15 seconds. Add bok choy, salt, sugar, and pepper and stir-fry 1 minute. Add 1 tablespoon water, cover, and cook until wilted, about 30 seconds. Uncover, stir-fry 5 seconds, then cover again, turn off flame, and let steam in residual heat until just tender, about 30 seconds more. Serve immediately.
|