Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper if desired.
In a mixing bowl, combine the ground meat, breadcrumbs, green onions, garlic, soy sauce, sesame oil, brown sugar, egg, black pepper, and red pepper flakes. Mix well until all ingredients are evenly incorporated.
Use your hands to form the mixture into meatballs, about 1 to 1.5 inches in diameter. You should have around 20-24 meatballs.
Place the meatballs on the prepared baking sheet, leaving a little space between each one.
Bake the meatballs in the preheated oven for 15-20 minutes, or until they are cooked through and the internal temperature reaches 160°F (71°C).
While the meatballs are baking, prepare the spicy mayo dip. In a small bowl, mix the mayonnaise, sriracha, lime juice, and a pinch of salt until smooth. Adjust the level of spice according to personal preference.
Once the meatballs are done, remove them from the oven and let them cool slightly before serving.
Serve the Korean BBQ meatballs warm, along with the spicy mayo dip for dipping.