BROWN sausage in a skillet over medium-high heat, breaking up sausage with a spoon as it cooks. Add onion and mushrooms; cook until almost tender (about 3 to 4 minutes). Remove from heat; drain if necessary.
MIX batter ingredients in a pre-sprayed 9 1/2-inch deep dish pie plate while sausage browns. Spread pizza sauce over batter.
TOP dough with cooked sausage and mushroom filling, spreading evenly. Firmly push toppings into batter. Sprinkle with cheese.
BAKE by placing in a COLD oven; set temperature to 350°F. Bake for 30 minutes or until done.
Recipe Note: If desired, batter may be mixed in a separate bowl. Proceed as directed above.