In a large mixing bowl, combine ground beef, plain breadcrumbs, egg, milk, minced onion, minced garlic, salt, black pepper, smoked paprika, and onion powder. Mix until just combined and form into meatballs.

Optional: Heat a skillet and sear meatballs for 3-4 minutes, turning to brown all sides. Transfer to slow cooker.

In a bowl, whisk together barbecue sauce, pineapple juice, brown sugar, soy sauce, apple cider vinegar, garlic powder, and ground ginger until smooth.

Place browned meatballs in the slow cooker, sprinkle drained pineapple chunks over them, and pour the sauce evenly.

Cover and cook on LOW for 3-4 hours or HIGH for 1.5-2.5 hours, stirring gently every hour, until hot throughout.

Optional: To thicken sauce, mix cornstarch with water and add to the slow cooker 20-30 minutes before serving.

Gently stir to coat meatballs in sauce before serving garnished with chopped green onions or parsley.