Make the sauce: In a small bowl, whisk together soy sauce, honey, garlic powder, cornstarch, and water. Set aside.
Cook the broccoli: Steam or microwave the broccoli until just tender (about 2–3 minutes). Set aside.
Sear the beef: Heat oil in a large pan or wok over medium-high heat. Add the beef and stir-fry for 2–3 minutes until browned.
Add the sauce: Pour the sauce over the beef. Simmer for 1–2 minutes until thickened.
Combine: Add broccoli to the pan and toss everything to coat well in the sauce. Cook for another minute, then serve.