In a bowl, toss the sliced steak with 1 tbsp cornstarch until coated.
Heat oil in a large skillet over medium-high heat. Cook the beef until browned, then transfer to a plate.
Add garlic and ginger to the skillet and sauté until fragrant.
Whisk together soy sauce, oyster sauce, brown sugar, beef broth, and remaining cornstarch.
Add broccoli to the skillet and cook until bright green and slightly tender.
Return the beef to the skillet, pour in the sauce, and toss until everything is coated and the sauce thickens.
Serve hot over steamed rice.