01 - In a large bowl, combine soy sauce, gochujang, sesame oil, honey, minced garlic, grated ginger, rice vinegar, brown sugar, black pepper, and chopped spring onions. Whisk until smooth and well blended.
02 - Place the lamb ribs in a large resealable bag or shallow dish. Pour the marinade over the ribs, turning to coat completely on all sides. Seal and refrigerate for at least 1 hour, preferably overnight for deeper flavor penetration.
03 - Preheat the oven to 320°F. Line a baking sheet with aluminum foil and place a wire rack on top. Arrange the marinated ribs on the rack in a single layer, reserving any leftover marinade for basting.
04 - Roast the ribs in the preheated oven for 1 hour, basting with the reserved marinade halfway through the cooking time to build a layered glaze.
05 - Preheat a grill or broiler to high heat. Transfer the roasted ribs to the grill and cook for 3 to 5 minutes per side until the exterior is deeply caramelized and lightly charred in spots.
06 - Remove the ribs from heat. Squeeze fresh yuzu juice generously over the top, then sprinkle with toasted sesame seeds, sliced spring onions, and sliced red chili if desired. Serve immediately with extra yuzu wedges alongside.