Preheat your oven to 325°F (163°C).
Place the baking bag in a large roasting pan.
Rub the chuck roast with the Bake in Bag seasoning mix from McCormick.
Pour 1 cup of water into the baking bag with the roast.
If using, peel and chop the vegetables into large chunks and add them to the bag.
Close the baking bag securely with the provided ties and make several slits in the top of the bag.
Place the roasting pan in the oven and cook for approximately 3 to 4 hours, or until the meat is fork-tender.
Once cooked, remove the bag from the oven and let the roast rest for 10-15 minutes before slicing.
