HEAT oven to 400ºF.
COOK crumbles, mushrooms, garlic and half the tomatoes in large nonstick skillet on medium heat 5 min. or until heated through, stirring frequently. Stir in pasta and cheese; spoon into peppers.
POUR remaining tomatoes into 8-inch square baking dish; top with peppers. Cover.
BAKE 30 min. or until heated through (160ºF).