Goose fat roast potatoes

Method

1. Scrub and peel the potatoes, reserving the peelings. Cut each potato in half or in quarters (depending on how big they are), aiming to end up with them all roughly the same size. Keep them submerged in a bowl of water in the fridge for up to 24 hours until ready to cook. Put the potato peelings in a food processor and whizz until chopped but not puréed – they’ll go a bit grey, but this is fine. Reserve two thirds of the whizzed peelings for the stuffing, if making our zero-waste Christmas dinner, and a third for the potatoes. Keep chilled in airtight containers. If not making the stuffing, only whizz one third (you could make potato peel crisps with the rest).
2. When ready to cook, heat the oven to 200°C fan/gas 7. Drain the potatoes, tip them into a large pan, cover with water and add a generous amount of salt. Bring to the boil over a medium-high heat, then cover and reduce to a simmer. Cook for 8 minutes until tender at the edges but still firm in the centre. Meanwhile put the goose fat in a large roasting tin, then transfer to the oven to heat up.
3. Drain the potatoes, leave in the colander to steam-dry for 3 minutes, then tip back into the pan, add the 1 tbsp salt and give the pan a shake to roughen up the edges. Carefully add the potatoes to the hot goose fat, using tongs to ensure each one is fully coated. Roast for 50 minutes, turning halfway through. Meanwhile, remove the one third of whizzed potato peelings from the fridge to come up to temperature.
4. Scatter the whizzed peelings over the potatoes along with the garlic and thyme. Return to the oven for 5-10 minutes until golden and crisp. Season with sea salt flakes and serve.