Cut the chuck roast into large chunks and season generously with salt on all sides, pressing it into the meat for even coverage.
Heat a large Dutch oven over medium-high heat, add the beef, and brown on all sides until a deep crust forms, then remove and set aside.
Add one diced onion and the minced garlic to the pot, sautéing for about 1 minute until fragrant and lightly softened.
Stir in the Italian seasoning, thyme, rosemary, and tomato paste, cooking for 1–2 minutes until the paste darkens slightly and coats the pot.
Deglaze with the red wine, scraping up all the browned bits, then add 2 cups of beef broth and return the beef to the pot, adding an extra cup of broth if needed to mostly cover the meat.
Add the quartered onion, carrots, whole garlic cloves, rosemary sprigs, and bay leaves, then cover with a lid and transfer to a 350°F oven.
Cook for 3–4 hours until the beef is fork-tender and easily pulls apart, then serve hot over mashed potatoes with plenty of sauce.