- Combine panko, egg and soy sauce in large bowl; let stand 5 minutes.
- Add ground beef and pineapple; mix until thoroughly combined. Shape into small meatballs, 1 inch in diameter. Arrange meatballs, 1 inch apart, on foil-lined shallow baking pan, lightly sprayed with cooking spray.
- Bake in 375º F oven 12 to 15 minutes, or until meatballs are cooked through.
- Immediately transfer meatballs into large bowl and pour in teriyaki sauce. Toss well to coat all pieces evenly with sauce.