Drain spinach well, pressing out excess liquid. In medium bowl, combine spinach, ricotta, egg, 4 tablespoons of the Parmesan, and the salt. Mix well. Place flour in shallow bowl. Drop ricotta mixture by teaspoonfuls onto flour; turn to coat with flour. Form into balls. Drop spinach balls into a large kettle or pot of gently boiling water; cook for 5 minutes. Remove with a slotted spoon; drain on paper towels. Transfer to serving plate. Drizzle with melted butter; sprinkle with remaining Parmesan and the parsley. Makes 8 side-dish servings.