Preheat the oven to 220°C. One hour before roasting remove the pork belly from fridge, place on trivet and roasting tray, massage the skin with the salt for 1 minute. Place belly in oven and roast for 25 minutes then turn down temp to 150°C and continue to cook for a further 2½ hours. Rest the cooked belly for at least 30 minutes. Add pigs blood and 5g of mace to thermomix and stir/cook to 70°C. Season to taste.
Cracker: In a saucepan add tapioca flour and 300mls of water, add reaming 5g mace and season to taste. Using a non-stick mat and a spatula spread paste on thinly and dry until breakable. Fry for 20 seconds at 190°C.
Artichokes: Place sliced butter on a perforated tray and freeze. Put the hickory chips into a wok and set alight, placing frozen butter on top, cover and allow smoke to penetrate for 5 minutes. Place 8 of the Jerusalem artichokes in a saucepan, add butter and season to taste. Cook gently until soft. Roast in frying pan with some of the cooked pork juices and add cooked barley at last minute. Season to taste. Put the vinegar and sugar in a saucepan, heat and stir until dissolved. Using a mandolin thinly slice the rest of the raw artichokes and add to pickling liquor for 2 minutes and then drain.
To serve: Slice the belly into 4 rectangles, place a generous tablespoonful of the blood purée on each plate, top with the belly, add a roasted artichoke on each then scatter barley and pickled artichokes. Finally add some roughly broken mace crackers.