Boil the potatoes for 10 mins, then drain. Rough up their surfaces with a fork or by shaking them in the pan with the lid on.
Melt the goose fat in a large, thickbottomed roasting tin on top of the stove. Tip in the potatoes carefully and turn them until they are evenly coated in the fat. Place on the top shelf of the oven (move the turkey down a shelf if necessary) and roast for 1-1¼ hrs, turning every now and then, until crisp and golden. Sprinkle with salt to serve.
This is one job that I like to do on the day as I think that potatoes peeled in advance and left in water overnight don’t roast as well.
Allow 800g Brussels sprouts for eight people and steam or boil for 15 mins until just tender. Serve plain or toss with butter and nutmeg.