Preheat your oven to 220 degrees Celsius. Next gently cook your onions over a medium heat until transparent and sticky then allow to cool. Blitz up your stuffing ingredients and then evenly spread across the butterflied pork shoulder then roll up the pork shoulder as tightly as possible using the butchers string to hold it together.
Pour a little boiling water over your pork skin before patting it dry and sprinkling with sea salt flakes. Place it in the oven for 20-25 minutes until the skin begins to turn golden. Add a drizzle of oil evenly coating the skin then reduce the heat to 160 degrees Celsius. Cover with foil and roast for around 3.5-hours, removing the foil for the last 30 minutes and increasing the heat to 200 degrees Celsius. Once cooked allow to rest for twenty minutes before serving.