Heat 1 tablespoon of vegetable oil in a large skillet over medium-high heat.
Add the ground beef to the skillet and cook, breaking it apart with a spatula, until browned and fully cooked, about 5-7 minutes. Drain excess fat if needed.
Season the beef with a pinch of salt and black pepper, then transfer it to a plate and set aside.
In the same skillet, add the remaining 1 tablespoon of vegetable oil and cook the broccoli florets over medium heat for 4-5 minutes, stirring frequently, until they are tender but still crisp.
Add the minced garlic to the skillet and sauté for 30 seconds, until fragrant.
In a small bowl, whisk together the soy sauce, oyster sauce, hoisin sauce, cornstarch, water, and sesame oil until smooth.
Return the cooked ground beef to the skillet with the broccoli, then pour the sauce over the mixture.
Stir everything together, cooking for 2-3 minutes, until the sauce thickens and evenly coats the beef and broccoli.
Taste and adjust seasoning if needed, adding more soy sauce or red pepper flakes for extra flavor.
Serve the ground beef and broccoli hot over rice, noodles, or as is.
Notes
For a gluten-free option, use tamari instead of soy sauce. You can also substitute chicken or turkey for ground beef.