Heat gas or charcoal grill. Cut 18x12-inch sheet of heavy-duty foil; place on large cookie sheet. Spray foil with cooking spray. Unroll dough onto sprayed foil. Starting at center, press out dough into 14x10-inch rectangle. Spray dough with cooking spray.
Invert dough rectangle directly onto grill rack; peel off foil and return foil to cookie sheet, sprayed side up. Cook uncovered on gas grill over medium-low heat or on charcoal grill 4 to 6 inches from medium-low coals 2 to 4 minutes or until bottom is golden brown. (Watch carefully to prevent burning.) With wide metal pancake turner, turn crust over. Cook 1 to 2 minutes longer or until bottom is set but not brown. Carefully remove from grill; place browned side up on foil. Close grill.
Top crust evenly with pizza sauce, spinach and mushrooms. Sprinkle with cheese. Slide pizza from foil onto grill. Cover grill; cook 3 to 6 minutes longer or until crust is golden brown and cheese is melted.
Have all toppings ready to go because the crust cooks quickly. If the crust is cooking too fast, move the pizza to a cooler part of the grill or reduce the heat.
Don't want to grill? Bake the pizza in the oven by following the directions on the can that use a prebake time.