Preheat the oven to 200°C. Place the pork in a roasting pan. Put plenty of chopped garlic, fresh sage leaves, peeled small onions and potatoes around it. Add 150mls white wine and 250mls chicken stock. Drizzle with a little olive oil and sprinkle with salt.
Place in the oven for 1-1/2 hours or until the juices run clear when a small knife is inserted into the middle of the pork. Remove from the oven and place the pork on a plate. Cover loosely with foil and rest 10-15 minutes.
Meanwhile, remove vegetables and keep them warm. Remove and discard the sage from the pan, pour off the fat and place the pan on high heat. Add 250mls more chicken stock, boil and scrape up the caramelised meat juices.
Slice the pork and serve with the vegetables and the strained sauce from the pan.