Mix together the salt, sugar, cumin, chilli, pepper and paprika and rub into the meat well.
Wrap in foil and put in the refrigerator to marinate for around 3 hours.
Heat the smoker and set the meat thermometer to 96°C (205°F). Stick the thermometer into the thickest part of the meat.
Put the meat in the smoker and leave to cook for up to 30 hours.
The temperature should not rise above around 100°C (212°F).
The meat is cooked when it reaches a core temperature of 96°C (205°F).
At this point, remove the meat from the smoker, wrap in foil and leave for one hour at 50°C (120°F) to rest.
Meanwhile, toast the bread in the oven (200°C, 400°F, gas 6) for around 5 minutes until crispy.
Pull the cooked meat apart using two forks and arrange on the slices of toast.
Top with the cabbage and serve garnished with parsley.