Start by making the mojo pork. Tip all the ingredients, except the pork, into a food processor with 1 tsp salt and a good grinding of black pepper. Blitz until finely chopped. Or, you can finely chop everything by hand. Pour into a large bowl or food bag and add the pork, turning it to coat well. If you've got time, leave to marinate in the fridge for at least 8 hrs, or up to 24 hrs. This is optional, but results in better flavour and makes the pork more tender. (If you don't have time to marinate, continue to step two.)

Heat the oven to 220C/200C fan/gas 7. Put the pork in a roasting tin along with any leftover marinade, then cover tightly with foil. Roast for 30 mins, then reduce the heat to 180C/160C fan/gas 4 and roast for a further 1 hr 30 mins. (Or, see tip below for cooking in a pressure cooker.) Remove from the oven and leave to cool, then slice thinly. If you don't have time to leave it to cool, shred it using two forks (you won't be able to slice it neatly while still warm). Once cool, will keep chilled for up to three days in an airtight container.

Brush the base of each panini with a little of the melted butter, then top with the mustard, sliced mojo pork, ham, gruyère and pickles. Sandwich with the tops of the panini, then brush the base and top with the remaining melted butter. Transfer the sandwiches to a large frying pan over a low heat, then put a flat saucepan lid on top to squish the sandwiches together. Put a heavy pan or can on top to weigh it down, and cook on each side for 4-5 mins until golden and the cheese is melted. Cut in half to serve.