My friend Betty once told me a riotous story of being invited to a Thanksgiving dinner and being asked to "bring something". When she arrived on the big day, there were 12, count 'em, sweet potato casseroles. Lesson learned: If you're going 'potluck' on Turkey Day, assign the side dishes. And you couldn't do much better than this deliciously rich gratin. It's a true example of over-the-top Thanksgiving cooking. Fair warning…this is one of the richest things (aka fatty) I’ve made in a very long time. But it was so delicious and really satisfying in tiny portions that I’d make again in a heartbeat…assuming I still had a pulse after consuming the pancetta and cream involved in the dish.
The other great thing about this dish is that it benefits from being made ahead. You can put the whole thing together a couple of days in advance and take it right up to the baking stage on the big day. It also is very forgiving and can be cooked longer than the time given which is always a huge help when you're putting together your Thanksgiving dinner. Another advantage to it's timing is that it's a lot easier to serve in beautiful little squares if it rests before serving.
All in all, it's a winner in every way.