1 (1 pound) loaf frozen bread dough, thawed
1 (10 ounce) package frozen chopped spinach, thawed and squeezed dry
1 cup chopped fresh mushrooms
1/2 cup chopped onion
1/4 teaspoon salt
1/8 teaspoon pepper
2 cups shredded part-skim mozzarella cheese
1/2 cup pizza sauce
2 tablespoons shredded Parmesan cheese
Place dough in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1 hour. Punch dough down; divide into thirds. On a lightly floured surface, roll one portion of dough into a 10-in. circle. Transfer to a 9-in. springform pan coated with nonstick cooking spray. Press dough onto bottom and up sides of pan.
In a bowl, combine the spinach, mushrooms, onion, salt and pepper. Sprinkle half of the mozzarella cheese over crust. Cover with spinach mixture; sprinkle with remaining mozzarella. On a lightly floured surface, roll out a second portion of dough into a 10- in. circle; place over cheese layer. Pinch together top and bottom crust. (Save remaining dough for another use).
Bake at 400 degrees F for 25-30 minutes or until lightly browned. Spread pizza sauce over top crust; sprinkle with Parmesan cheese. Bake 5-6 minutes longer or until cheese is melted. Let stand for 5 minutes before cutting.