Place dried porcini mushrooms in a small bowl and cover with boiling water, letting stand for 20 minutes or until softened.
Drain mushrooms, rinse well and finely chop. Set aside.
Heat olive oil in a large soup pot over medium heat. Add celery, carrots and onions. Stirring frequently, cook for 5 minutes until tender.
Add the 3 cups of fresh assorted mushrooms and cook for another 5 minutes until they begin to soften.
Add beef broth, barley, thyme, basil, salt, and pepper. Bring to a boil, then reduce heat and simmer for 45 minutes, or until barley is tender.
Stir in minced parsley before serving.