in a 5-quart soup pot, simmer barley in water or stock with bay leaf until soft (about 1 hour).
Add carrots and parsnip and simmer 15 minutes longer.
In a separate skillet, gently saute onions and garlic in oil or butter until wilted.
Add mushrooms and thyme.
Cook until soft.
Then add onion mushroom mixture and white pepper to the pot of barley.
Bring to a boil, remove from heat, and let stand at least 5 minutes before serving.
Sprinkle with parsley and ladle into preheated bowls.
Note: This soup reheats beautifully, but expect it to thicken.
You can transform it into a stew by adding 1/2 cup lentils and sliced celery to the soup pot 45 minutes before the barley is done.