In a bowl, mix ground beef, breadcrumbs, egg, milk, salt, pepper, garlic powder, and onion powder. Form into small meatballs.
Heat oil in a pan over medium heat. Fry the meatballs until browned on all sides. Remove and set aside.
In the same pan, sauté bell pepper and onion until slightly soft.
Add pineapple chunks, ketchup, vinegar, brown sugar, and soy sauce. Stir well.
Bring to a simmer, then add the meatballs back into the pan.
Stir in the cornstarch slurry to thicken the sauce. Cook for 2-3 minutes until the sauce is glossy.
Serve hot over rice or noodles.