In large bowl, stir Bisquick mix and cold water until dough forms. Divide dough into 2 parts, with 1 part slightly larger. On surface sprinkled with Bisquick mix, press or roll larger part of dough into 16x14-inch rectangle. Fold crosswise into thirds; place in centre of baking dish and unfold. Press dough on bottom and up sides of dish. Sprinkle with 1 cup of the cheese; top with 3/4 cup of the pizza sauce, the meat mixture, mushrooms, pepper and 1 1/2 cups of the cheese.