Reduce the heat to 200C/180C fan/gas mark 6 and continue to cook the pork for around 80-90 minutes, or until the meat has an internal cooking temperature of 72C. A couple of times while roasting, spoon Marsala from the pan over the shallots, or if it has cooked away, add 100ml of hot water to them – you want them soft and golden by the end, but not burnt.