COOK pasta as directed on package, omitting salt.
MEANWHILE, heat dressing in large saucepan on medium-high heat. Add potatoes and garlic; cook 3 min., stirring frequently. Stir in broth; bring to boil. Cover; simmer on medium-low heat 10 min. Stir in broccoli and peppers; simmer, covered, 3 min. or until vegetables are tender. Add Neufchatel and thyme; cook and stir until Neufchatel is completely melted and mixture is well blended.
DRAIN pasta; place in large bowl. Add sauce; mix lightly. Sprinkle with Parmesan.