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.
PLACE vegetables in blender. Add broth and water; 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.