Preheat the oven to 200C/400F/Gas 6.
Rub the oil over the pork and season with salt and freshly ground black pepper.
Heat an ovenproof griddle pan and griddle the pork for a few minutes on both sides, then transfer to the oven and cook for 8-10 minutes, or until golden-brown and completely cooked through.
For the caramelised apple, place the butter, sugar and apple slices into a pan over a medium heat and cook gently for five minutes, or until softened and golden-brown.
For the creamed leeks, heat the oil in a frying pan and cook the onion and leek over a low heat for five minutes.
Add the cream and cheese and simmer gently for 3-4 minutes.
To serve, place the pork onto a plate with the caramelised apple and creamed leeks spooned alongside.
