1. Preheat broiler.
2. Place 2 of the tortillas on a cookie sheet (do not grease).
3. Spread tortillas with pizza sauce. Top each with pepperoni, mushrooms, 1/2 cup of the cheese and then the other 2 tortillas.
4. Broil about 2 minutes, until tortillas are very lightly browned.
5. Flip quesadillas over and top with 1/2 cup cheese. Broil another 2 minutes, until cheese is melted. Top with parsley.