Get a frying pan on a high heat. Don't add any oil. Meanwhile, peel and halve the onions (if using a large onion cut into 6-8 wedges). Peel and segment the apple, discarding the peel. Season the pork with salt, pepper and sage on both sides, and rub some olive oil into them.
When the pan is hot add the onions cut side down. Leave for around five minutes until a char develops, then add the pork and apples. Turn the heat down to medium. (If your chops have a decent layer of fat, using tongs hold them fat-side down in the pan until starting to colour, then lay them down.
Continue cooking for 5 - 10 minutes until cooked to your liking, turning a couple of times to colour both sides. Turn the apples and onions as you go too. When the pork's done, turn the heat down and add the creme fraiche. Add a splash of hot water to loosen the sauce down to a creamy consistency. Allow to bubble for a minute or two and season to taste. Serve with rice or mash.