01 - Sprinkle salt and freshly ground black pepper evenly over the beef chunks.
02 - Heat olive oil in a large skillet over medium-high heat and sear beef until browned on all sides, about 5 minutes, then transfer to the slow cooker.
03 - In the same skillet, add onion, carrots, and celery; sauté for 4 to 5 minutes until softened. Incorporate garlic and cook for 1 additional minute, then transfer all vegetables to the slow cooker.
04 - Pour red wine into the skillet; simmer for 2 minutes, scraping up browned bits. Add this liquid to the slow cooker with crushed tomatoes, tomato paste, beef broth, oregano, thyme, bay leaves, and crushed red pepper flakes if desired. Stir to combine.
05 - Cover and cook on low heat for 8 hours until beef is tender and shreds easily.
06 - Remove bay leaves, shred the beef directly in the slow cooker with two forks, and stir to blend flavors. Adjust seasoning to taste.
07 - Approximately 20 minutes before serving, prepare pappardelle according to package instructions. Drain and set aside.
08 - Serve the shredded beef ragu atop the pappardelle, then garnish with freshly grated Parmesan cheese and fresh basil leaves.