In a large skillet over medium-high heat, add the ground beef, breaking it apart as it cooks for about 5-7 minutes until browned.

Drain excess fat, return skillet to medium heat, and add the finely diced onion, sauté for 2-3 minutes until translucent.

Stir in the minced garlic and ground ginger, cooking for about 1 minute until fragrant.

Add the shredded green cabbage to the skillet, stirring well and cooking for 4-5 minutes until tender yet crunchy.

In a separate bowl, whisk together the soy sauce, sesame oil, rice vinegar, and optional red pepper flakes, then pour over the beef and cabbage.

Stir well, remove from heat, and garnish with sliced green onions and toasted sesame seeds before serving.