HEAT dressing in large skillet on medium heat. Add onions; cook and stir 5 min. or until crisp-tender. Stir in eggplant; cook 5 min., stirring frequently. Add mushrooms, zucchini and peppers; cook and stir 5 min.
STIR in tomatoes; bring to boil. Simmer on medium-low heat 15 min. or until vegetables are tender, stirring occasionally. Pour into casserole dish; top with cheese. Cover.
HEAT oven to 350°F. Bake casserole 25 to 30 min. or until heated through. Sprinkle with parsley.
