Preheat oven to 400 degrees F . Line 2 baking sheets with foil; lightly coat the foil with cooking spray. Set baking sheets aside. For filling, in a medium bowl, stir together spinach, cream cheese, 2 tablespoons Parmesan cheese, green onion, and pepper. Set aside.

Unroll pizza dough on a lightly floured surface; roll dough into a 15-inch square. Using a pizza cutter or sharp knife, cut into twenty five 3-inch squares. Spoon a slightly rounded teaspoon of filling onto the center of each square. In a small mixing bowl use a fork to combine egg white and water. Brush edges of dough squares with egg white mixture. Lift a corner of each square and stretch dough over filling to opposite corner, making a triangle. Press edges with the tines of a fork to seal.

Arrange the calzones on prepared baking sheets. Prick tops of calzones with fork. Brush tops of calzones with egg white mixture. Sprinkle with remaining 1 tablespoon Parmesan cheese. Bake one sheet at a time for 8 to 10 minutes or until golden brown. Cool slightly on baking sheets. Serve warm.

The spinach filling may be made the day ahead. Cover and chill in refrigerator. Let stand at room temperature for 30 minutes to soften, if necessary.