Wash and peel fresh chestnuts, rinse, then make a nick in the skin on the flat side of each and simmer in a pan of boiling water for 40 minutes max one hour.
Then peel, taking care to remove both the outer shell (quite easy) as well as the inner brown membrane (trickier).
It’s much more simple to do the latter when they’re still hot, so work in small batches.
Slowly heat the oil with the onions in a pan over low heat then add the prosciutto and crumbled chestnuts.
In meantime cook the Pappardelle in plently of salted boiling water, drain the pasta and let it cook in the pan with the sauce until the sauce is fully absorbed.
Serve in warm plates adding a tussock of fresh sage and enjoy!