In a large mixing bowl, combine ground beef, plain breadcrumbs, eggs, and milk. Add minced onion, garlic, salt, black pepper, smoked paprika, and onion powder. Mix gently until just combined, then scoop and roll into 1–1½ inch meatballs.

If preferred, brown the meatballs in a skillet over medium-high heat for 2–3 minutes on each side until golden brown.

In a separate bowl, whisk together barbecue sauce, pineapple juice, brown sugar, soy sauce, apple cider vinegar, and optional garlic powder.

Layer the browned or raw meatballs in the slow cooker, pour the prepared sauce over them, and add pineapple chunks. Stir gently to coat.

Cover and cook on LOW for 4–5 hours or on HIGH for 2–3 hours until meatballs are cooked through.

For a thicker glaze, mix cornstarch with water and add during the last 20–30 minutes of cooking.

Once cooked, ladle the meatballs onto a serving platter and garnish with chopped green onions or parsley.