Preheat the broiler. Line a rimmed baking sheet with foil and grease with butter. In a large mixing bowl, combine the pork, cheese, breadcrumbs, apple, onion, 3 tablespoons parsley, the egg, 1 1/2 teaspoons salt and 1/4 teaspoon pepper. Shape into 16 meatballs and arrange on the baking sheet. Broil the meatballs until golden and cooked through, 8 to 10 minutes.
Meanwhile, in a pot of boiling, salted water, cook the noodles until al dente. Drain, then return to the pot and toss with the butter and remaining 5 tablespoons parsley; season with salt and pepper. Divide the noodles among 4 plates; top with 4 meatballs each.
