Follow these simple steps to make incredible grilled short ribs:

1. Prepare Marinade: In a large bowl, whisk together soy sauce, brown sugar, rice vinegar, sesame oil, minced garlic, grated ginger, black pepper, and cayenne pepper (if using).
2. Marinate the Ribs: Place the short ribs in a resealable plastic bag or a shallow dish. Pour the marinade over the ribs, ensuring they are well-coated. Seal the bag or cover the dish, then refrigerate for at least 2 hours, or overnight for best results.
3. Preheat the Grill: Preheat your grill to medium-high heat (about 400°F or 200°C).
4. Remove Ribs from Marinade: Take the short ribs out of the marinade, allowing excess liquid to drip off. Discard the marinade.
5. Grill the Ribs: Place the ribs on the grill, bone-side down. Grill for about 5-7 minutes on each side, or until they develop a nice char and are cooked to your desired doneness.
6. Check for Doneness: Use a meat thermometer to ensure the internal temperature reaches at least 145°F (63°C) for medium-rare.
7. Rest the Ribs: Once grilled, remove the ribs from the grill and let them rest for about 5-10 minutes to allow the juices to redistribute.
8. Garnish: Sprinkle sesame seeds and chopped green onions over the ribs for added flavor and presentation.
9. Slice and Serve: Slice between the bones to create individual portions, and serve hot.

These steps will guide you in creating mouthwatering grilled short ribs that are sure to impress!