Preheat the oven at 400 F.
In a large bowl, combine the ground beef, garlic powder, onion powder, Italian seasoning, Parmesan cheese, breadcrumbs, salt, pepper, egg, and milk. Mix together until thoroughly blended.
Using a tablespoon for measuring and your hands for rolling, start making those meatballs. Form meatballs that are approximately 1 ½ inches in diameter and place the meatballs in a single layer in the pan. I just rolled them between my palms and got 18 average size meatballs.
On medium high heat in a large oven proof skillet (such as cast iron), brown meatballs on all sides, carefully turning so they don't break apart. Cook them for about 10 minutes. They will not be cooked throughs point and will finish cooking in the oven.
Next, pour the marinara sauce over the meatballs and sprinkle the Mozzarella cheese over the sauce. Bake for 30-35 minutes.
Sprinkle with parsley and serve immediately.