2kg floury potatoes (we used Maris Piper), cut into chunks
200g duck fat or goose fat (reserved from the confit turkey - see 'goes well with' opposite)
flaky sea salt
On Christmas Eve, put the potatoes in a large saucepan and cover with cold salted water. Bring to the boil, reduce the heat to a simmer and cook for 2-3 mins until slightly tender. Drain and give them a good shake in the colander. Tip into a large roasting tin lined with baking parchment and leave, uncovered, in the fridge overnight.
When your turkey crown goes in, put the duck fat in your largest roasting tin and heat in the oven. After 10 mins, transfer your cold potatoes to the hot duck fat – you should hear them sizzle as they hit the tin. Toss to coat in the fat and season well with flaky sea salt, then spread them in a single layer so they crisp up better. Roast for about 1 hr 30 mins, turning a few times, to evenly brown. Serve immediately.