Let’s dive into the step-by-step process to make this delicious dish:

1. Preheat your oven to 300°F (150°C).
2. In a large bowl, combine soy sauce, rice vinegar, brown sugar, sesame oil, garlic, ginger, hoisin sauce, red pepper flakes, and water. Whisk until well blended.
3. Place the beef short ribs in a large roasting pan. Pour the marinade over the ribs, turning them to ensure they are fully coated.
4. Cover the pan tightly with aluminum foil and place in the preheated oven. Roast for 3.5 to 4 hours, or until the meat is tender and easily pulls away from the bone.
5. Remove the foil during the last 30 minutes of cooking to allow the sauce to thicken and caramelize. Baste the ribs occasionally with the pan juices for maximum flavor.
6. Once done, remove the ribs from the oven and let them rest for a few minutes. Garnish with sliced green onions and sesame seeds before serving.

From my experience, patience is key in this process. Letting the ribs roast slowly ensures that they soak up all those incredible flavors, just like those family meals I cherished growing up.