In a large mixing bowl, combine the ground beef or pork, soy sauce, sesame oil, brown sugar, garlic, ginger, green onions, egg, breadcrumbs, gochugaru, and black pepper. Mix everything together until fully incorporated.
Using your hands, shape the meat mixture into small meatballs, about 1 ½ inches in diameter, and place them on a baking sheet lined with parchment paper.
Preheat your oven to 400°F (200°C). Bake the meatballs in the preheated oven for 15-20 minutes, or until they are cooked through and golden brown on the outside.
In a small bowl, whisk together the mayonnaise, sriracha, rice vinegar, sesame oil, honey, soy sauce, and lime juice until smooth and well combined. Taste and adjust the seasoning for heat and sweetness as needed.
Once the meatballs are cooked, transfer them to a serving plate and drizzle with a bit of the spicy mayo dip or serve it on the side for dipping. Garnish with additional chopped green onions if desired.
