In a small bowl, mix the soy sauce, oyster sauce, cornstarch, and a pinch of salt and pepper. Set aside.
Heat the vegetable oil in a large skillet or wok over medium-high heat. Add the minced garlic and ginger, and sauté for about 30 seconds until fragrant.
Add the ground beef to the skillet, breaking it apart with a spatula. Cook until browned and cooked through, about 5-7 minutes. Drain excess fat if necessary.
Stir in the broccoli florets and cook for another 3-4 minutes until they are bright green and tender-crisp.
Pour the sauce mixture over the beef and broccoli, stirring to coat everything evenly. Cook for an additional 2-3 minutes until the sauce thickens.
If using, sprinkle red pepper flakes for added heat. Adjust seasoning with salt and pepper as needed.
Serve hot over cooked rice or noodles.