Use paper towels to thoroughly pat the entire surface of the chuck roast completely dry. Season the meat generously on all sides with kosher salt and freshly ground black pepper, pressing the seasoning firmly into the tissue so it adheres securely.

Heat the 2 tablespoons of olive oil in a large, heavy skillet over high heat. Once the oil begins to shimmer, lay the roast in the pan and sear undisturbed for 4 to 5 minutes until a deep, mahogany brown crust locks onto the surface; flip and repeat on all sides, including the edges, then transfer the meat into the ceramic basin of your slow cooker.

Reduce the skillet heat to medium and scatter the thick onion wedges into the hot pan drippings. Sauté for 3 minutes, using a wooden spoon to scrape up the dark, caramelized beef bits anchored to the bottom of the pan, then stir in the minced garlic and tomato paste for exactly 60 seconds until fragrant.

Pour the beef broth, Worcestershire sauce, dried thyme, and dried rosemary directly into the warm skillet, stirring to combine the elements into a unified liquid baseline, then remove from the heat.

Arrange the chunks of carrots and halved baby red potatoes snugly around the seared chuck roast inside the slow cooker basin, tucking the two bay leaves beneath the liquid line. Pour the warm herbed broth from your skillet directly over the beef and vegetables.

Cover with a tight-fitting lid and cook on Low for 8 to 9 hours (or on High for 5 to 6 hours). Avoid lifting the lid during the cycle; maintaining constant, uninterrupted ambient heat is essential for the tough collagen chains to completely unravel into a meltingly tender state.

Once the timer finishes, carefully lift the pot roast and vegetables out of the liquid using a slotted spoon and place them onto a warm serving platter, covering loosely with aluminum foil to trap the moisture.

Pour the remaining warm cooking juices through a fine mesh strainer into a large glass measuring cup, letting it sit undisturbed for 3 minutes so the clear lipid fats naturally float to the very top.

Skim exactly a quarter-cup of that hot beef fat from the surface and drop it into a medium saucepan over medium heat (supplement with unsalted butter if you run short). Whisk in the quarter-cup of all-purpose flour continuously for 2 minutes to cook out the raw flour flavor and toast the roux into a golden-brown paste.

Slowly stream 2 cups of the warm, defatted cooking juices into the saucepan while whisking rapidly to prevent lumps from forming. Bring the gravy to a gentle boil, reduce the heat to low, and simmer for 3 to 5 minutes until it transforms into a thick, glossy, and velvety sauce. Adjust seasonings to taste, shred the tender beef into thick chunks, and ladle the rich gravy generously over the roast and root vegetables.