Trim any excess fat from the beef and cut it into large chunks (about 4–5 cm pieces). Season with salt and pepper. Heat 2 tablespoons of olive oil in a large heavy-based pan over medium-high heat. Brown the beef on all sides, about 3-4 minutes per side. Once browned, transfer the beef to a slow cooker or set aside.
In the same pan, reduce the heat to medium and add 1 tablespoon of olive oil. Add the diced onion, carrots, and celery. Sauté for 5-7 minutes, stirring occasionally, until the vegetables are softened. Add the minced garlic and cook for another 1-2 minutes until fragrant.
Pour in the red wine and let it simmer for 3-4 minutes, scraping up any browned bits from the bottom of the pan. Stir in the tomato puree, chopped tomatoes, beef stock cube, thyme, and water. Mix everything well. Season with a pinch of salt and pepper.
Pour the vegetable and wine mixture over the beef in the slow cooker. Stir gently to combine, ensuring the beef is mostly submerged in the sauce.
Cover the slow cooker and cook on low for 8-10 hours or on high for 4-5 hours, until the beef is tender and easily pulled apart with a fork.
Once the beef is tender, use two forks to shred it into bite-sized pieces. Stir the shredded beef back into the sauce and let it cook for another 15-20 minutes on low heat.
About 15 minutes before serving, cook the pappardelle or pasta of choice according to package instructions until al dente. Drain and reserve a cup of pasta water in case you need to thin out the sauce.
Toss the cooked pasta with the beef ragu. If the sauce is too thick, add a little reserved pasta water to loosen it. Serve with freshly grated Parmesan cheese and sprinkle with chopped parsley. Enjoy your rich, flavorful beef ragu!
