In a large bowl, combine the ground beef, bread crumbs, onion, egg, garlic powder, salt, and pepper. Mix until combined.
Form the mixture into 1-inch balls and place in the slow cooker.
In a medium bowl, combine the ketchup, brown sugar, Worcestershire sauce, apple cider vinegar, dry mustard, red pepper flakes, and pineapple juice. Stir until combined.
Pour the sauce over the meatballs, and stir to coat.
Cover and cook on low for 4-6 hours.
Serve warm.
Interesting Facts
Hawaiian meatballs use a combination of sweet and savory flavors to create a unique flavor.
The slow cooker is an ideal way to cook the meatballs, as it helps keep them moist and tender.
These meatballs are a great addition to any potluck or party.