Crispy Potato Balls

Name: Crispy Potato Balls
Ingredients: 1 1/2 cups Mashed Potatoes, recipe follows, cold; 1/4 cup all-purpose flour; 1 large egg; 1 tablespoon chopped fresh parsley, plus more for garnish; 1/4 cup grated Parmesan, plus more for garnish; 1/2 cup shredded mozzarella; 1/4 teaspoon freshly ground black pepper; 3/4 cup dried breadcrumbs; Vegetable oil, for frying; Kosher salt; 5 pounds russet or Yukon gold potatoes; 3/4 cup (1 1/2 sticks) salted butter, plus more for topping; One 8-ounce package cream cheese, softened; 1/2 cup half-and-half, or more if desired; 1/2 teaspoon seasoned salt, or to taste; 1/2 teaspoon freshly ground black pepper, or to taste