01 - Preheat the oven to 320°F (160°C).
02 - Whisk together soy sauce, honey, hoisin sauce, brown sugar, rice vinegar, sesame oil, tomato ketchup, garlic, ginger, chili flakes, and black pepper in a bowl.
03 - Place the beef ribs in a large roasting dish and pour half the marinade over them, turning to coat evenly. Reserve the remaining marinade.
04 - Cover the dish tightly with aluminum foil and bake for 2 hours, turning the ribs once halfway through.
05 - While ribs bake, pour the reserved marinade into a small saucepan and simmer over medium heat for 6 to 8 minutes until slightly thickened. Set aside.
06 - Remove foil from ribs, increase oven temperature to 400°F (200°C). Brush ribs generously with the thickened glaze.
07 - Return ribs to oven uncovered for 20 to 30 minutes, basting once or twice, until sticky and caramelized.
08 - Transfer ribs to a serving platter and sprinkle with sesame seeds and sliced spring onions.