In a bowl, whisk together soy sauce, brown sugar, garlic, sesame oil, rice vinegar, ginger, and black pepper to make the marinade.
Place the beef short ribs in a large resealable plastic bag or a shallow dish. Pour the marinade over the ribs, making sure they are well coated. Marinate in the refrigerator for at least 2 hours, or overnight for best flavor.
Preheat the grill to medium-high heat. Remove the ribs from the marinade, shaking off any excess.
Grill the short ribs for 3-4 minutes per side, or until cooked to your desired doneness.
Serve the Korean BBQ Short Ribs hot off the grill, garnished with chopped green onions and toasted sesame seeds. Enjoy with steamed rice and your favorite Korean side dishes!