1. In small bowl, stir together soy sauce, sherry, sugar, cornstarch, white pepper, pepper flakes, mustard, and 2 tablespoons water until sugar dissolves; set aside.

2. In 12-inch nonstick skillet with tight-fitting lid, heat oil over high heat until just smoking. Add broccoli stems in even layer and cook, without stirring, until browned on bottoms, about 2 minutes. Add florets to skillet and toss to combine; cook, without stirring, until bottoms of florets brown, about 2 minutes longer.

3. Add remaining 3 tablespoons water and cover skillet; cook until broccoli is bright green but still crisp, about 2 minutes. Uncover and continue to cook until water has evaporated, broccoli stems are tender, and florets are tender-crisp, 1 to 2 minutes more. Transfer broccoli to large plate.

4. Reduce heat to medium-high and add pork to now-empty skillet. Cook, breaking pork into small pieces, until no pink remains, about 2 minutes. Add garlic and ginger; cook, stirring constantly, until fragrant, 15 to 20 seconds. Stir sauce to recombine and return broccoli to pan with sauce. Toss and cook until sauce is thickened, 5 to 10 seconds. Remove pan from heat and stir in scallions and sesame oil. Serve immediately.

Serves 4 as a side dish or 2 as a main course