Preheat oven to 375F. On a lightly floured surface roll two-thirds of the dough into a 12-inch circle. (If necessary, let dough rest once or twice during rolling.) Place circle in a greased 9-inch springform pan, pressing dough 1-1/2 inches up the sides. Sprinkle with 1/2 cup of the mozzarella. Top with the Meaty Pizza Filling. Mix spinach, egg, and remaining mozzarella. Spread spinach mixture over Meaty Pizza Filling.
Roll remaining dough into a 10-inch circle. Cut into 8 wedges. Arrange wedges on spinach mixture, slightly overlapping edges and sealing edges to bottom crust along edge of pan. Brush top with melted butter and sprinkle with Parmesan
Bake, uncovered, in the preheated oven for 40 to 45 minutes or until filling is hot and crust is done. If necessary, cover with foil the last 10 minutes of baking to prevent overbrowning. Cool on a wire rack for 10 minutes. Remove sides of springform pan. Cut into wedges. Serves 8.
Meaty Pizza Filling
In a large skillet cook bulk Italian sausage and chopped onion until sausage is brown, drain. Pat meat with paper towels. Stir in pizza sauce; mushrooms, drained; one package sliced pepperoni; dried basil, crushed; and dried oregano, crushed.