barley recipe

1 cup pearl barley, rinsed - 2 tablespoons olive oil - 1 medium onion, chopped - 2 cloves garlic, minced - 2 carrots, chopped - 2 celery stalks, chopped - 1 medium potato, peeled and chopped - 1 can (400 grams) diced tomatoes - 8 cups vegetable or chicken broth - 1 bay leaf - 1 teaspoon dried thyme - Salt and pepper to taste - Fresh parsley for garnish (optional)