In a large mixing bowl combine turkey, spinach, the shredded cheese, and 1/2 cup of the pizza sauce. On a lightly floured surface, roll one package of pizza dough out to a 12x12-inch square. Cut into 4 6x6 inch squares.
Place about 1/2 cup of the turkey mixture onto half of each square to within about 1 inch of edge. Moisten edges of dough with water and fold over, forming a rectangle or a triangle. Pinch or press with a fork to seal edges. Prick tops of calzones with a fork; brush with milk and place on a greased baking sheet.
Repeat with remaining dough and turkey mixture. If desired, sprinkle top of each calzone with about 1/2 teaspoon grated Parmesan or Romano cheese. Bake calzones in a 375 degree F. oven about 18 minutes or until golden brown. Serve with remaining pizza sauce. Makes 4 calzones.
To Make-Ahead: Prepare and bake calzones as above. Cool, wrap, label, and chill overnight or freeze up to 1 month. To serve, thaw frozen calzones in refrigerator overnight. Unwrap and place on baking sheet. Bake, uncovered, in a 350 oven for 15 to 18 minutes or until heated through.