Bring some water to the boil in a large saucepan, add in the pork and blanch the for 5 mins.
Drain the water, rinse the pork and return to the saucepan, add in all the other ingredients and bring to the boil.
Reduce the heat and simmer covered for 2.5-3 hrs until the meat is tender, turning the pork a few times during cooking.
When done remove the pork from the liquid and reduce the remaining liquid by boiling it uncovered for about 20 minutes or until it thickens.
Slice the pork and brush the soy sauce reduction on the sliced pork.
Assemble the sandwiches starting with the brioche bun base, then the red-cooked pork, then the coleslaw and toasted sesame seeds before topping with the bun lid.