1 leek, finely chopped
2 rosemary sprigs, leaves picked
360g/12陆oz trompetti pasta
sea salt and freshly ground black pepper
300g/10陆oz cooked chestnuts, roughly chopped
4 tbsp extra virgin olive oil
140g/5oz mascarpone
grated pecorino, to serve
80驳/2戮辞锄 pancetta, finely chopped