Slice the flank or skirt steak against the grain into thin strips. Combine with soy sauce, peanut oil, and cornstarch in a medium bowl and let marinate for about 10 minutes.

Whisk together the chicken stock, Shaoxing wine, dark soy sauce, and brown sugar in a separate bowl until well combined.

Bring 1/4 cup of water to a boil in a nonstick skillet. Add broccoli florets, cover, and steam for about 1 minute until tender-crisp. Transfer to a plate.

Heat 1 tablespoon of oil in the skillet until shimmering. Add marinated beef, cooking undisturbed for 30 seconds, then flipping until lightly charred but still pink.

Add minced garlic and grated ginger to the beef in the skillet, cooking for about 30 seconds to release aromas.

Return the steamed broccoli to the skillet, pour in the sauce mixture, and cook together for about 1 minute until thickened. Serve immediately.