Brown sausage and onion in large skillet. Drain fat. Stir in pizza sauce, mushrooms, pepperoni, garlic, and parsley.
Flour counter and roll two thirds of bread dough into 12 inch circle. Place bread in greased 9 inch springform pan, pressing dough 1 1/2 inches up sides. Sprinkle bottom of dough with 1/2 cup of mozzarella cheese. Spoon meat filling over cheese, then sprinkle on remaining cheese.
Roll remaining dough into 10 inch circle on lightly floured surface. Cut circle into 10 to 12 wedges. Arrange wedges on top of meat mixture, slightly overlapping edges and sealing ends to bottom crust along edge of pan. Brush top with melted margarine or butter and sprinkle with parmesan cheese.
Bake 40 minutes or until filling is hot and bread is done. If necessary, cover with foil the last 10 minutes of baking to prevent overbrowning. Cool on wire rack for 10 minutes. Remove sides of springform pan. Cut into wedges.