2) To make the panini, heat the panini in a warm oven or under a preheated grilling element until lightly toasted. Preheat the panini press.
3) Spread four panini halves with salsa verde. Top with a layer of sliced porchetta or pork, fontina, rocket and onions. Cover each with one of the remaining halves of panini.
4) Transfer one sandwich to the panini press and heat until the cheese melts. Transfer to a board and cut into wedges, Repeat with the the other sandwiches.
Serve with any remaining salsa verde.