Cut the steak along the grain into 3-inch strips, then slice the strips across the grain into 1/4-inch wide pieces.

Whisk the brown sugar, cornstarch, soy sauce, hoison sauce, chile-garlic sauce, ground ginger, and garlic powder together in a large bowl.

Transfer half of the sauce (about 1/4 cup) to a small bowl and set aside.

Add the steak to the remaining sauce in the bowl, toss to coat, and set aside for 5 minutes.

Heat the oil in a large skillet over medium-high heat until shimmering.

Add the steak and arrange into a single layer.

Sear undisturbed until browned on one side, about 1 minute.

Toss and continue to cook until the other side of the meat is browned, about 1 minute more.

Add the broccoli and the reserved sauce and stir to combine.

Cover and cook until the broccoli is crisp-tender and the beef is cooked through, 4 to 5 minutes.

Serve topped with scallions