Low 'N Slow Mushroom Barley Soup

INGREDIENTS

• 1/4 cup pearl barley
• 1 cup boiling water
• 2 tablespoons canola oil
• 1 onion, finely chopped
• 1 stalk celery, finely chopped
• 1 carrot, finely chopped
• 6 cups white mushrooms, halved if large
• 3 cloves garlic, minced
• 1 tablespoon tomato paste
• 6 cups beef stock
• 1 teaspoon dried oregano
• 1/2 teaspoon salt
• 1/2 teaspoon freshly ground black pepper
• 1 tablespoon Worcestershire sauce