We are using the porchetta technique of a rolled and stuffed pork belly. This is perfectly suited to the ferocious, dry heat of an airfryer, and could easily feed 4 or so people for less than £15.
Kick off with the pork belly. Ideally this will take place the day (or even two days) before you want to make the buns to ensure you have incredibly crackling. If the butcher/supermarket hasn't already scored the skin, do this, then get a small roasting tin, mix the salt and baking powder together and lay the pork belly skin side down on top of the salt mix. Make sure all the skin has contact with the salt, then leave it uncovered in the fridge until it's cooking time.
Carefully run a knife under the skin so you can open up the belly like a book. Scatter liberally with the thyme leaves and garlic, then roll up the meat into a tight spiral, wrapping the spiral in the skin and tying with butchers twine. Watch the video for greater clarity!
Place the log in the airfryer basket along with the apples and set the heat to 150°C and the timer to an hour. After about 30 minutes or so, remove the apples and blitz them with the sugar to make the apple sauce.
After an hour, increase the heat to 200°C for a final 10 minutes. By this point you should have perfect, crispy puffed crackling and succulent meat. Leave it to rest briefly while you toast the buns.
Assemble the buns with mustard, apple sauce, slices of roast pork and watercress and eat hot.