Preheat your oven to 190ºC/375ºF/gas 5. Blitz the onions in the food processor until finely chopped, then tip into a large bowl. Tear the stale bread into small chunks and whiz into breadcrumbs. Add these to the bowl, then crush and crumble your chestnuts in there too. Tip your diced pork into the food processor with the sage leaves, bacon, a level teaspoon of white pepper and a good pinch of salt. Finely grate in a quarter of the nutmeg, the zest of half a lemon and just 2 or 3 gratings of orange or clementine zest. Pulse until you’ve got some chunks and some mush, it won’t even take a minute, then tip into the mixing bowl.
Because the pork is raw, you’re committed to seasoning it well so add another pinch of salt and white pepper, then get your clean hands in there and scrunch it all up until well combined.
Take just under half of the stuffing out of the bowl to use for your turkey, then transfer the rest to a lovely earthenware-type dish that you can serve from. Use your hands to break it up and push it about, then flatten it all down. Pop it in the oven to cook for 50 minutes to 1 hour until bubbling and crispy. If you’re doing it as part of your Christmas lunch, you want to get it on about the same time as your spuds.
When done, you can pour away any excess fat before serving if you want to. It will be soft, juicy and succulent on the inside, then gnarly, crispy and chewy on the outside. Delicious.