Heat 2 Tbsp. dressing in large saucepan on medium heat. Add onions; cook 5 min. or until crisp-tender, stirring occasionally. Add eggplant, zucchini, peppers, garlic and remaining dressing; mx well. Cook 5 min. or until crisp-tender, stirring occasionally. Add tomatoes; cook 15 min. or until tomatoes are softened, stirring occasionally.
Stir in broth; bring to boil. Simmer on medium-low 15 min. or until vegetables are tender, stirring occasionally.
Blend soup, in batches, in blender until desired consistency. Return to saucepan. Stir in cheese; cook 2 min. or until heated through, stirring frequently.