In a large pot or Dutch oven, heat the olive oil over medium-high heat. Add the beef stew meat and season with salt and black pepper. Brown the beef on all sides for about 5-7 minutes. Remove the beef from the pot and set aside.
In the same pot, add the onions, carrots, and celery. Sauté for 5 minutes until the vegetables start to soften.
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 barley, thyme, rosemary, and bay leaf. Bring the mixture to a boil.
Once boiling, reduce the heat to low, cover the pot, and let it simmer for about 1 hour.
After 1 hour, add the green beans and corn. Simmer for an additional 15-20 minutes or until the barley is tender and the vegetables are cooked through.
Taste the soup and adjust the seasoning with additional salt and pepper as desired.
Remove the bay leaf before serving. Ladle the soup into bowls and garnish with chopped parsley, if using.