Baby bok choy with ginger and garlic

2 pounds baby bok choy (8 to 10), halved lengthwise and soaked in cold water to remove any dirt
2 teaspoons minced peeled fresh ginger
2 garlic cloves, thinly sliced
1 tablespoon plus 1 teaspoon toasted sesame oil
1/4 cup tamari soy sauce
2 tablespoons oyster sauce

Bring a large pot of water to a boil. Add the bok choy (in two batches, if necessary), and cook until tender, 5 to 7 minutes. Drain in a colander; let stand at least 5 minutes. Transfer to a serving dish.
Meanwhile, cook the ginger and garlic in oil in a small saucepan over medium-low heat, stirring, until soft, about 8 minutes. Add the tamari and oyster sauce; cook, stirring, until heated through, about 30 seconds more. Pour the sauce over the bok choy; toss to coat.

SERVES 4 TO 6