Pat the sides and top of a chuck roast with brown sugar. Double wrap in foil to ensure that the juices remain with the roast. Cook 10 hours at 225 - 250 degrees F.
Combine sauce ingredients and simmer 15 minutes.
Separate roast into large chunks. Combine cooking juices with sauce and marinate meat for 4 hours.
Serve on toasted, butter buns and top with grated cheese.