Generously season the pork on all sides. Heat the olive oil in a heavy-bottomed saucepan with a lid just large enough to hold the pork. Brown the meat on all sides, then remove. Pour away the fat.
Melt the butter in the pan, add the garlic with the sage leaves (if using) and, before the garlic begins to colour, return the pork to the pan. Add enough hot milk to come three-quarters of th