Preheat your oven to 350°F (175°C).

In a large mixing bowl, combine the ground meat, rolled oats, chopped onion, salt, black pepper, and Worcestershire sauce. Mix until just combined.

Using a small cookie scoop, portion out the meat mixture and roll it into balls about 1 inch in diameter. Place in a greased baking dish.

In a medium mixing bowl, whisk together the cornstarch, brown sugar, mustard, ketchup, and teriyaki sauce until smooth.

Slowly stir in the white vinegar until well blended.

Pour the sauce over the meatballs in the baking dish, ensuring they are well-coated.

Bake the meatballs for 25 minutes, uncovered, until cooked through.

Let the meatballs rest for a few minutes before serving. Serve over rice or mashed potatoes.