Takes 1 hour 20 minutes
If roasties don’t crisp up, it’s usually because they’ve not been cooked for long enough. Lots of recipes suggest you can crisp up a potato in half an hour but that’s not really possible – allow 50 minutes, or even an hour. Optional extras include sprigs of rosemary or thyme, or a few whole cloves of garlic, in their skins, added for the last 20 minutes or so of cooking.
Peel and chop the potatoes several hours in advance, and store covered in cold water. (If you have an air fryer, you can cook them a day ahead and reheat and crisp up at 200°C/400°F for 6 -7 minutes.)
1. Heat the oven to 200°C (400°F), gas mark 6. Set a large pan of salted boiling water over a high heat. Bring back to the boil and add the potatoes. Simmer for 10 minutes to parboil, then remove from the heat and drain. Allow to steam-dry for 10 minutes.
2. While the potatoes steam, place the goose fat and vegetable or sunflower oil in a roasting tin (or 2) and place in the oven to heat up.
3. Return the potatoes to their pan, cover with a lid and give them a shake, just enough to roughen their cut edges, which will help absorb the fat and create crunch.
4. Remove the hot tin from the oven and place the potatoes carefully into the hot fat. Turn each potato once or twice in the fat to coat. Return to the oven and roast for at least 50 minutes, turning them after about half an hour and then every 15 minutes or so, until they are crisp, golden brown all over and crunchy. Sprinkle sea salt flakes over to serve.
• 1.5kg (3lb 5oz) floury potatoes, ideally Maris Pipers, peeled and cut into large chunks
• 2½ tablespoons goose fat
• 1 tablespoon vegetable or sunflower oil
• sea salt flakes, to serve