Melt butter in large saucepan. Add mushrooms, celery, carrot and onion and cook until crisp tender. Dissolve bouillon granules in boiling water and add to vegetables. Add orzo.
Bring to a boil; reduce heat. Simmer, uncovered, 5-8 minutes or until orzo is tender but still firm. Stir in turkey, parsley, thyme and pepper; heat through.
Please note that some ingredients and brands may not be available in every store.