Preheat oven to Gas 4, 180 °C, Fan 160 °C.
Trim the pork loins of any fat. Melt the butter in large frying pan and fry the pork for 5 mins each side, to brown. Remove the chops from the pan and place onto 4 large pieces of foil, and put into a roasting tin.
Add the onion and mushrooms to the butter remaining in pan and cook for 5 mins, to soften. Stir in cider and lemon juice and bring to boil. reduce the liguid over a high heat until reduced by half, then remove from heat and stir in creme fraiche. season well.
Place a quarter of the mushroom mixture on top of each piece of pork, then shape the foil into neat parcels and seal well. Bake for 40 minutes until the meat is tender.
To serve place each parcel on place open carefully so no juices escape. serve with small new potatoes and green beans.