Heat a large skillet or wok over medium-high heat. Add the sesame oil and swirl to coat. Add the ground beef and break it apart with a spatula. Cook until browned and no longer pink, about 5–7 minutes. Drain excess fat if needed.

Toss in the minced garlic and grated ginger. Stir constantly for 1 minute until fragrant but not burned. You should smell a sharp, zesty aroma that signals the base flavors are blooming.

Add the cabbage and carrots. Stir well to mix everything evenly. Cook for 4–5 minutes, stirring frequently. The cabbage should start to wilt but still have a slight crunch.

Add soy sauce, rice vinegar, and oyster sauce (if using). Stir well to coat the beef and vegetables. Let it bubble for a minute to meld the flavors.

Give your cornstarch slurry a quick stir and pour it into the pan. Stir continuously for another 1–2 minutes. The sauce should thicken slightly and cling to the meat and cabbage.

Taste and adjust seasoning—add more soy sauce or vinegar if needed. Stir in crushed red pepper flakes if you like a kick. Remove from heat and top with green onions.

Serve hot in bowls as-is, or spoon over warm jasmine or brown rice for a heartier option.