1. Preheat oven to 425 degrees.
2. Cook ground beef, mushrooms, and green pepper in a medium frypan till meat is no longer pink, drain.
3. Stir in the mozzarella cheese and the 1/3 cup pizza sauce.
4. Unroll pizza dough.
5. Roll or stretch dough into a 10 x 15 inch rectangle.
6. Cut dough into 6- 5 inch squares.
7. Spoon some of the meat mixture onto one-half of each square.
8. Brush dough edges with water.
9. Lift a corner and stretch dough over meat mixture to opposite corner.
10. Seal the edges by pressing with the tines of a fork.
11. Place calzones on a greased baking sheet.
12. Prick tops with a fork to allow steam to escape.
13. Brush with the milk.
14. If desired, sprinkle with parmesan cheese.
15. Bake in the preheated oven for 8 to 10 minutes or till golden brown.
16. Let stand for 5 minutes before serving.
17. If desired, serve with warmed pizza sauce.