01 - Season beef chunks thoroughly with salt and freshly ground black pepper.
02 - Heat olive oil in a large skillet over medium-high heat. Brown beef chunks on all sides, approximately 2–3 minutes per side, then transfer to slow cooker.
03 - In the same skillet, add onion, carrots, and celery; sauté until softened, about 5 minutes. Add garlic and cook an additional minute. Stir in tomato paste and cook 1 minute more.
04 - Transfer sautéed vegetables to slow cooker. Add crushed tomatoes, red wine, dried oregano, dried basil, bay leaves, crushed red pepper flakes (if using), and sugar. Stir to integrate.
05 - Cover and cook on low setting for 8 hours, or on high for 4–5 hours, until beef is deeply tender and shreds easily.
06 - Remove bay leaves. Shred beef directly in slow cooker using two forks. Stir in whole milk and adjust seasoning as needed.
07 - Cook pappardelle pasta according to package instructions. Drain and portion onto serving plates.
08 - Ladle beef ragu over pasta. Garnish with freshly grated Parmesan cheese and fresh basil or parsley.