Heat oil in a large pan or wok over medium-high heat. Add ground beef, season lightly with salt and pepper, and cook until browned (5–7 minutes). Remove excess fat if needed.
Toss in garlic, ginger, and onion. Stir-fry for 2–3 minutes until fragrant.
Add shredded cabbage and stir-fry for 4–5 minutes until slightly softened but still crisp.
Pour in soy sauce, oyster sauce, rice vinegar, sesame oil, and chili flakes. Mix well and cook another 2–3 minutes.
Adjust salt, spice, or acidity as needed.
Spoon stir fry into a bowl or plate, gently press into a mold or stack neatly for presentation.
Garnish with green onions and sesame seeds.
