Place the beef mince, ½ cup bulgogi marinade, panko crumbs, finely diced onion, ginger, spring onions, salt and pepper into a bowl. Mix to combine.
Take 1 tablespoon of mixture and roll into a ball using wet hands.
Bake in the oven for 10 minutes. Place onto the prepared baking tray.
Sprinkle with sesame seeds.Remove the meatballs from the oven and brush the tops with the remaining bulgogi marinade. Place back into the oven for a further 5 minutes. Serve immediately with steamed rice and finely sliced spring onions.