In a large pot or Dutch oven, heat some olive oil over medium heat. Add the beef and cook until browned on all sides. Remove the beef from the pot and set aside.
In the same pot, add the diced onion, sliced carrots, and chopped celery. Cook until the vegetables are softened, about 5 minutes. Add the minced garlic and cook for an additional minute.
Return the browned beef to the pot. Stir in the beef broth, diced tomatoes (with their juices), bay leaf, dried thyme, salt, and pepper. Bring the soup to a boil, then reduce the heat and let it simmer for about 1 hour, or until the beef is tender.
Meanwhile, cook the pasta according to the package instructions until al dente. Drain and set aside.
Once the beef is tender, remove the bay leaf from the soup. Add the cooked pasta and let it simmer for another 5 minutes to allow the flavors to meld together.
Taste the soup and adjust the seasoning if needed. Ladle the soup into bowls, garnish with fresh parsley, and serve hot.