Heat the olive oil in a large pot over medium heat. Add the beef cubes and cook until browned on all sides. Remove the beef and set it aside.
Add the onion to the same pot and cook until it softens. Stir in the garlic and cook for one minute more.
Stir the tomato paste and thyme into the onion mixture. Cook for another minute.
Return the beef to the pot. Pour in the beef broth and add the bay leaf. Bring the mixture to a simmer.
Add the carrots, parsnips, and potatoes. Cover the pot and let it simmer gently for about 90 minutes, or until the beef and vegetables are tender.
Remove the bay leaf. Taste and add salt and black pepper as needed.