Heat the oil. In a large pot, heat the olive oil over medium heat.
Brown the beef. Add the beef stew meat seasoned with salt and pepper, browning it on all sides.
Sauté the vegetables. Toss in the chopped onion, celery, and carrots. Cook until the vegetables start to soften, about 5-7 minutes.
Add mushrooms and garlic. Stir in the cremini mushrooms and minced garlic, cooking for another 2 minutes until fragrant.
Introduce herbs. Mix in the dried thyme and tomato paste, cooking for an additional minute.
Add broth. Pour in the beef broth and Worcestershire sauce, then add the bay leaves. Bring to a simmer.
Stir in barley. Add the rinsed pearl barley and cover the pot, cooking for about 1-1.5 hours, or until the beef is tender and the barley is cooked.
Final touches. Remove the bay leaves, adjust seasoning if necessary, and enjoy!