1Move oven rack to lowest position. Heat oven to 450°F. Spray 12-inch pizza pan with cooking spray. In large bowl, stir Bisquick mix, water and oil with fork until soft dough forms; beat vigorously 20 strokes. Cover; let stand 8 minutes.
2Pat or press dough in bottom and 1 inch over side of pizza pan. Place string cheese along edge of dough, overlapping if necessary. Fold 1-inch edge of dough over and around cheese; press to seal.
3Bake 6 to 7 minutes or until lightly browned around edges.
4Spread pesto over warm crust. Sprinkle with 1 cup of the mozzarella cheese; top with bell peppers and remaining 3/4 cup cheese. Bake 11 to 14 minutes or until crust is golden brown and cheese is melted.