Since the ground beef filling becomes very hot during baking, let the calzones cool a little after you cut them open.
For filling, in a medium skillet cook beef or pork and onion until meat is brown and onion is tender. Drain fat. Stir in undrained tomatoes, broccoli, Italian seasoning, and pepper. Bring to boiling. Reduce heat. Simmer, uncovered, about 15 minutes or until most of the liquid has evaporated, stirring occasionally. Remove from heat. Stir in green pepper and olives.
Unroll one package pizza dough. On a lightly floured surface, roll dough into a 15x10-inch rectangle; cut into six 5-inch squares. Repeat with remaining package pizza dough.
Divide filling among the 12 squares; sprinkle with cheddar cheese. Brush edges with water. Lift one corner and stretch dough over to the opposite corner. Press edges of dough well with a fork to seal.
Arrange calzones on a greased or parchment-lined baking sheet. Prick tops with a fork. Brush tops with milk; sprinkle with Parmesan cheese. Bake in a 425 degree F oven about 10 minutes or until golden brown. Serve with pizza sauce, if desired. Makes 6 servings.