Preheat oven to 400 F. Spray baking sheet with nonstick cooking spray; set aside. Combine ham, apple, cheese and mustard, if desired, in medium bowl; set aside. Roll out pizza dough on lightly floured surface to 15x10-inch rectangle. Cut into 6 (5-inch) squares. Top each square evenly with ham mixture. Moisten edges with water. Fold dough over filling to form triangle. Press edges with fork to seal. Place on prepared baking sheet. Prick tops of each turnover with fork. Bake about 15 minutes or until golden brown. Serve warm or allow to cool on wire rack about 1 hour.
