1Move oven rack to lowest position; heat oven to 450°F. Spray 12-inch pizza pan with cooking spray. In medium bowl, stir Bisquick mix, hot water and oil with fork until soft dough forms; beat vigorously 20 strokes. Let stand 8 minutes.
2Pat or press dough in bottom and 1 inch over side of pizza pan. Lightly press 1/4 cup of the pepperoni along edge of dough. Place string cheese over pepperoni along edge of dough, overlapping if necessary. Fold 1-inch edge of dough over and around cheese and pepperoni; press to seal. Bake 7 minutes.
3Spread pizza sauce over partially baked crust. Sprinkle with 1 cup of the Italian cheese, remaining 1/2 cup pepperoni, the mushrooms, bell pepper and olives. Sprinkle with remaining 1 cup cheese.
4Bake 9 to 12 minutes longer or until crust is golden brown and cheese is melted.