Add the beef chunks, onion, carrots, celery, and garlic to the slow cooker.
Pour in the crushed tomatoes and beef broth.
Stir in the bay leaves, oregano, salt, and black pepper.
Cover and cook on low for 8 hours until the beef is very tender.
Remove the bay leaves and shred the beef directly in the sauce with two forks.
Cook the pappardelle pasta in a large pot of salted boiling water according to package directions.
Drain the pasta and divide it among four bowls.
Spoon the ragu over the pasta and top with grated Parmesan cheese.