(Serves 4)

The cooking of this dish goes quickly, so makes sure you have all your ingredients ready before turning on the stove. If you wish, ½ cup shiitake mushrooms, stemmed and minced, can be added to the dish.

2 tablespoons soy sauce

1 tablespoon dry sherry

1 teaspoon sugar

½ teaspoon cornstarch

¼ teaspoon ground white pepper

¼ teaspoon red pepper flakes

¼ teaspoon dry mustard

2 tablespoons water

2 tablespoons vegetable oil

1 pound green or yellow wax beans, ends trimmed, cut into 2-inch pieces

3 medium garlic cloves, minced

1 tablespoons minced fresh ginger

3 scallions sliced thin

1 teaspoon toasted sesame oil

In a small bowl, stir together soy sauce, sherry, sugar, cornstarch, white pepper, chili flakes, mustard, and water until sugar dissolves; set aside.

Heat oil in a 12-inch nonstick skillet over high heat until just smoking. Add beans and cook, stirring frequently, until crisp-tender and skins are shriveled and blackened in spots, 5 to 8 minutes (reduce heat to medium-high if beans darken too quickly). Transfer beans to large plate.

Reduce heat to medium, add a teaspoon of oil and add minced shiitakes to now-empty skillet. Cook 2-3 minutes, until mushrooms are soft. Add garlic and ginger, cook, stirring constantly, until fragrant, 15-20 seconds. Stir sauce to recombine and return beans to pan with sauce. Toss and cook until sauce is thickened, 5-10 seconds. Remove pan from heat and stir in scallions and sesame oil. Serve immediately.