Heat oil in a large pot over medium-high
heat. Season beef with 1/4 tsp of the salt
and the black pepper and add to pot; sauté
5 minutes, turning once. Add onion and
garlic; cook 3 minutes, stirring occasionally.
Add stock, 3 cups water, carrots and
celery. Cover and simmer 60 minutes,
stirring occasionally. Add tomatoes,
mushrooms, barley, remaining 3/4 tsp of
the salt and the thyme. Simmer 30
minutes, covered, stirring occasionally.
Stir in peas and simmer 2 minutes.
Garnish with parsley, if desired.