Heat olive oil in a large pot over medium heat. Add the beef cubes and brown them on all sides, about 5-7 minutes.
Remove the beef from the pot and set aside. In the same pot, add the diced onion, carrots, and celery. Cook until they are soft, about 5 minutes.
Stir in the minced garlic and cook for another minute until fragrant.
Return the browned beef to the pot. Pour in the beef broth and add the pearl barley, thyme, rosemary, salt, and pepper.
Bring the mixture to a boil, then reduce the heat and let it simmer for about 1 hour, uncovered.
After 1 hour, add the frozen peas and cook for an additional 10-15 minutes until the barley is tender and the beef is cooked through.
Taste and adjust seasoning if necessary. Serve hot, garnished with fresh parsley if desired.