01 - Generously season beef chunks with salt and freshly ground black pepper.
02 - Heat olive oil in a large skillet over medium-high heat and sear beef on all sides until deeply browned, about 2 to 3 minutes per side. Transfer beef to the slow cooker.
03 - In the same skillet, add chopped onion, diced carrots, and celery. Cook until softened, approximately 5 minutes. Add minced garlic and sauté one additional minute. Stir in tomato paste and cook for 1 minute to enhance flavor.
04 - Transfer the sautéed vegetables to the slow cooker. Add crushed tomatoes, red wine, dried oregano, dried basil, bay leaves, crushed red pepper flakes if using, and sugar. Stir to combine thoroughly.
05 - Cover and cook on LOW for 8 hours or on HIGH for 4 to 5 hours until the beef is tender and easily shreds with a fork.
06 - Remove bay leaves. Shred the beef directly in the slow cooker using two forks. Stir in whole milk and adjust seasoning to taste.
07 - Cook pappardelle pasta according to package directions until al dente. Drain well.
08 - Divide pasta onto serving plates and spoon the beef ragu on top. Garnish with freshly grated Parmesan cheese and fresh herbs such as basil or parsley.