Preheat the oven to 400 degrees F and line a baking sheet with parchment paper.
In a mixing bowl combine the ground beef, panko breadcrumbs, egg, milk, onion powder, and salt. Mix with your hands until the ingredients are evenly distributed.
Scoop out tablespoon-sized portions and roll them into small ovals. Use a knife to make shallow curved lines across the top of each oval to create a brain-like pattern.
Place the shaped meatballs on the prepared baking sheet and bake for 12 minutes.
Transfer the baked meatballs to a large skillet set over medium heat. Pour the barbecue sauce over them and stir gently to coat.
Simmer for 5 minutes, stirring once, until the sauce thickens slightly and clings to the meatballs.
Sprinkle with the chopped parsley before serving.