Heat the oven to 325°F and pat the roast dry.
Season the beef with the salt and pepper, dust it with the flour, and brown it in the oil in a Dutch oven over medium-high heat for 4 to 5 minutes per broad side.
Move the roast to a plate, cook the onions in the pot for 8 minutes until browned at the edges, and stir in the garlic for 30 seconds.
Return the roast, add the broth, Worcestershire and thyme, cover, and bake for 2 hours.
Add the carrots and potatoes around the beef, cover, and bake for 60 to 75 minutes more until the vegetables are tender and the roast is about 200°F and fork-tender.
Rest the meat for 15 minutes, skim the fat from the pot liquid, and simmer the onion gravy on the stovetop for 5 minutes if it needs to thicken.