Heat the olive oil in a large pot over medium-high heat. Add the beef stew meat and sear until browned on all sides. Remove the meat and set aside.
In the same pot, add the onion, carrots, celery, and garlic. Sauté for about 5 minutes until softened.
Add the seared beef back into the pot. Pour in the beef broth, water, and diced tomatoes. Add the potatoes, green beans, bay leaf, and thyme—season with salt and pepper.
Cook: Bring the soup to a boil, then reduce the heat to low. Cover and let simmer for about 1 hour 30 minutes, or until the beef is tender.
Serve: Remove the bay leaf. Ladle the soup into bowls, garnish with fresh parsley, and enjoy!