To make the meatballs, whisk together egg, bread crumbs, milk, nutmeg, salt, and pepper.
Stir in pork, chopped parsley, and Parmesan. Set aside.
In a 6 quart stock pot, heat oil to medium high heat. Add celery and onion. Cook and stir for 5 minutes or until tender.
Add Escarole, chicken broth, 2 cups of water, and whole parsley leaves. Bring to a boil and then reduce heat to a simmer.
Drop rounded tablespoons of pork mixture into broth. Cover and simmer for 10 minutes or until meatballs are cooked through.
Top with additional Parmesan cheese and black pepper. Add salt and pepper according to your tastes.