HEAT oven to 400ºF.
TOSS parsnips and onions with dressing. Spread into single layer on baking sheet. Bake 30 to 35 min. or until vegetables are tender; cool slightly.
PLACE vegetables in blender. Add water and broth; blend until smooth. Pour into large saucepan.
ADD Velveeta; cook on medium heat 10 to 15 min. or until Velveeta is melted and soup is heated through, stirring frequently.