Begin by seasoning your chuck roast or boneless short ribs generously with salt and pepper. In a Dutch oven, heat olive oil over medium-high heat until shimmering. Add the beef and sear for about 5-7 minutes, turning occasionally, until browned on all sides. Remove the beef and set aside.

In the same pot, reduce heat to medium and add chopped onions. Sauté for 4-5 minutes, stirring, until translucent and fragrant. Incorporate minced garlic and sauté for an additional 1-2 minutes.

Stir in tomato paste, cooking for 1 minute. Deglaze the pot with beef stock, scraping browned bits from the bottom. Follow with balsamic vinegar, crushed tomatoes, diced tomatoes, parmesan rind, bay leaves, thyme, basil, sugar, and red pepper flakes. Stir gently and let simmer.

Return seared beef to the pot and cover with a lid. Reduce heat to low and slow-cook for 2.5 to 5 hours. The meat should shred easily with a fork.

Once tender, remove meat and shred into bite-sized pieces using two forks. Return shredded beef to sauce, stirring to combine. Adjust seasoning with salt and skim off excess fat. Discard bay leaves.

Cook pappardelle pasta according to package instructions until al dente. Drain and plate pasta, ladle ragu over top, and garnish with parsley and grated parmesan.