Combine the flour, salt and pepper in a large bowl. Place the roast in the bowl and completely coat with seasoned flour.
Place the roast into the Dutch oven and brown on all sides, about 3 - 4 minutes each side. Remove the roast, place it on a plate, and set aside.
Add the onions to the pan and cook for 1 minute. Reduce heat to medium and stir in the reserved flour. Cook, stirring often, until the mixture is golden in color, 3 - 5 minutes.
Quick Tip - If pan seems too dry add additional oil before adding the onion slices.
Stir in the Guinness, beef stock, and bay leaf. Use a wooden spoon or spatula to scrape the bottom of the pan to remove any cooked on bits.
Return the roast to the pan, cover, reduce heat and simmer for 3 - 3.5 hours or until beef is tender and easily shreds with a fork.
Add the potatoes and carrots, cover and continue cooking until vegetables are cooked firm-tender, 25 - 30 minutes.
Remove the roast and separate into small chucks with two forks, or slice thin.
Serve in a bowl with vegetables covered in gravy, or arrange slices on a plate and spoon gravy over the meat. Garnish with parsley and serve.
Notes
For wheat-free gravy: do not coat the beef in flour, simply season with the salt and pepper then sear it in the oil. Mix 3 tablespoons of cold water with 2 tablespoons of cornstarch to create a slurry. Remove the roast from the pan and whisk in the slurry to thicken before serving.
Guinness Drought can be substituted for the extra stout, or use your favorite brand of stout beer.