HEAT dressing in large saucepan on medium-high heat. Add mushrooms and onions; cook and stir 5 min. or until onions are crisp-tender.
STIR in broth; bring to boil. Add quinoa; stir. Return to boil; cover. Simmer on low heat 16 to 18 min. or until liquid is absorbed and quinoa is tender. Remove from heat; fluff with fork. Let stand, covered, 5 min.
STIR in cheese and parsley.