Trompetti with chestnut and pancetta sauce

By Gennaro Contaldo From Saturday Kitchen Ingredients 360g/12½oz trompetti pasta 4 tbsp extra virgin olive oil 1 leek, finely chopped 80g/2¾oz pancetta, finely chopped 300g/10½oz cooked chestnuts, roughly chopped 2 rosemary sprigs, leaves picked 140g/5oz mascarpone sea salt and freshly ground black pepper grated pecorino, to serve …