Chop the cabbage into bite-size pieces so it cooks evenly and remains slightly crisp. Fresh cabbage holds texture better than pre-cut versions. Keep it ready before starting the cooking process.
Heat sesame oil in a skillet over medium-high heat and cook the beef until browned. Break the meat apart while cooking to create even texture. Browning develops flavor for the whole dish.
Move the cooked beef aside and sauté garlic and ginger in the same pan. Cooking them briefly releases their aroma without burning. This step infuses flavor into the oil and beef.
Add cabbage and red pepper flakes, stirring to combine. Cook until cabbage softens slightly but still retains some crunch. Overcooking can make it mushy.
Mix soy sauce, hoisin sauce, and sweetener in one bowl. In another bowl, mix beef broth and cornstarch, then combine both mixtures. Pour sauce into the skillet.
Stir everything together and allow the mixture to simmer. The sauce thickens quickly and coats the beef and cabbage evenly. Adjust seasoning if needed.
Turn off the heat and stir in green onions. Sprinkle sesame seeds on top if desired. Serve hot for best flavor and texture.