Heat 2 tablespoons of olive oil in a large pot over medium-high heat. Add the beef cubes and season with salt and pepper. Cook until the beef is browned on all sides, about 5-7 minutes. Transfer the beef to a plate and set aside.
Return the browned beef to the pot. Add the beef broth, pearl barley, dried thyme, and bay leaf. Bring the mixture to a boil, then reduce the heat to low, cover, and simmer for about 1 hour, or until the barley and beef are tender.
Final Touches:
If using, add the frozen peas in the last 10 minutes of cooking. Season with additional salt and pepper to taste. Remove the bay leaf before serving.
Serve:
Ladle the soup into bowls and garnish with fresh chopped parsley. Serve hot with crusty bread on the side.