In large bowl combine the ground beef, Italian sausage, bread crumbs, Parmesan cheese, eggs, milk, parsley, Italian seasoning and garlic powder. Mix well.
Using a tablespoon or ice cream scoop, scoop up the meat. Roll into balls.
Heat oil in skillet over medium-high heat. Evenly place the meatballs on the skillet. Cook for 4-5 minutes. Turn over the meatballs and cook for an additional 4-5 minutes until browned.
Remove the meatballs from the skillet and set aside. Drain the oil from the skillet. Pour marinara sauce on the skillet and spread around. Return the meatballs to the skillet. Evenly place mozzarella cheese on top of the meatballs.
Bake at 350 degrees F preheated oven until cheese is melted, about 15 minutes.
Garnish with parsley and Parmesan cheese. Serve over pasta, or on its own.