Preheat your oven to 350°F (175°C) and prepare your baking sheet or loaf pan.

In a large mixing bowl, combine ground beef, onion, eggs, milk, breadcrumbs, garlic, ketchup, parsley, Worcestershire sauce, salt, black pepper, and Italian seasoning. Mix gently.

Shape the mixture into a loaf and place it in the prepared pan.

Mix ketchup, brown sugar, and apple cider vinegar in a bowl for the glaze. Set aside half for later.

Bake the meatloaf for 45 minutes, then brush with remaining glaze and return to oven.

Continue baking for an additional 15-20 minutes until the internal temperature reaches 160°F (71°C).

Let the meatloaf rest for about 10 minutes before slicing and serving.