This recipe can be prepared in a slow cooker or an oven capable of maintaining 250 degrees.
Preheat oven to 400.
Spread the sliced onions on the bottom of an enamel lined Dutch oven or slow cooker.
Mix together the spices, mustard and salt and rub over the pork roast thoroughly, then place the roast flesh side down on the onions with the skin and fat facing up.
Mix the cider, cider vinegar and maple syrup and pour over the pork.
Put the uncovered pot (or the ceramic insert of your slow cooker) in the oven for 15 – 30 minutes until the pork skin is golden brown and liquid is simmering nicely.
Turn the oven down to 250.
If you are using a slow cooker, return the ceramic to the slow cooker and put it on high till it is boiling again then set it to low. Cover the Dutch oven before putting it back into the oven.
Cook for 4 to 6 hours until the pork is tender and falling apart.
Remove the pork from the pot, shred it and remove any bones.
Reduce the sauce until it is thick and sticky, recombine and serve.