Season the pork slices with salt and pepper, brown on both sides in a little olive oil in a frying pan and transfer to a large braising pan. Add the onion/leeks mixture and add a few stalks of rosemary
Picture . Pour over almost all of a bottle of good red wine until the meat is almost covered. Cook over a high heat until simmering and transfer to the oven at 325°F/170°C/Reg3 and cook for two hours turning the meat half way through.