01 - Generously season the beef chunks with salt and pepper on all sides.
02 - Heat olive oil in a large skillet over medium-high heat. Sear the beef chunks until browned on all sides, about 2–3 minutes per side. Transfer the browned beef to the slow cooker.
03 - In the same skillet, add the onion, carrots, and celery. Cook for 4–5 minutes until softened. Add the garlic and tomato paste, stirring constantly for 1 minute to bloom the flavors. Transfer the mixture to the slow cooker.
04 - Pour the crushed tomatoes, beef broth, and red wine into the skillet to deglaze, scraping up any browned bits from the bottom. Pour this liquid into the slow cooker. Add oregano, thyme, basil, red pepper flakes, and bay leaves. Stir gently to combine.
05 - Cover the slow cooker and cook on low heat for 8 hours, or until the beef is fork-tender and easily shreds.
06 - Remove the beef from the slow cooker and shred it using two forks. Return the shredded meat to the sauce. Discard the bay leaves. Taste the sauce and adjust seasoning with salt and pepper if necessary.
07 - Cook the pappardelle pasta in a large pot of salted boiling water according to package instructions until al dente. Drain well.
08 - Toss the cooked pasta with the beef ragu sauce, or serve the sauce ladled over the pasta. Garnish with freshly grated Parmesan cheese and chopped parsley.