01 - Heat olive oil in a large Dutch oven over medium-high heat. Add beef cubes in batches, browning them on all sides. Transfer browned beef to a plate.
02 - In the same pot, add diced onion, sliced carrots, celery, and mushrooms. Sauté for 5 minutes until softened.
03 - Stir in minced garlic and cook for 1 minute until fragrant.
04 - Return beef to the pot. Add diced potatoes, undrained diced tomatoes, rinsed pearl barley, tomato paste, Worcestershire sauce, bay leaves, thyme, rosemary, salt, and black pepper.
05 - Pour in beef broth and water. Stir well to combine. Bring to a boil, then reduce heat to low. Cover and simmer for 1.5 to 2 hours, stirring occasionally, until beef and barley are tender.
06 - Stir in frozen peas during the last 10 minutes of cooking. Taste and adjust seasoning as needed.
07 - Remove bay leaves before serving. Serve hot, optionally with crusty bread.