Make the dry rub for the meat by combining the brown sugar, paprika, garlic powder, onion powder, salt and pepper.
Coat the bottom of the roast with 1 tablespoon of the yellow mustard then sprinkle half of the dry rub over it.
Flip the meat and coat the top with the other tablespoon of yellow mustard and cover it with the remaining dry rub ingredients.
Carefully pour the beef broth into the crockpot, being careful not to wash the dry rub off the meat.
Cover and cook on low for 8 hours.
Once the meat is done cooking, shred the meat with 2 forks.
Butter two pieces of bread and place the cheese on either side of the bread, then place the meat in between the slices of bread and place on a hot griddle or skillet.
Cook on each side until the bread is golden brown and the cheese is melted.
Remove from griddle, cut in half and enjoy!