Using your hands, mix the ground beef, breadcrumbs, milk, salt, worcestershire sauce, pepper, onion and egg in a large bowl. Shape into 1 ½” balls. Arrange in a casserole dish and bake for 20-25 minutes until the meatballs reach an internal temperature of 165°F.
Meanwhile, cook the rotini according to the package instructions.
Heat the marinara sauce in a small saucepan on low heat until warmed.
Serve the pasta with the sauce, topped with meatballs. Garnish with parmesan cheese and fresh parsley.