Jamie Oliver Make Ahead Potatoes are parboiled potatoes that are cooled, chilled, and later roasted at high heat. This method allows the potatoes to dry out slightly, helping them crisp up far better than potatoes cooked entirely at the last minute.
Peel the potatoes and cut them into evenly sized chunks. Keeping the size consistent helps them cook at the same rate during both boiling and roasting.
Place the potatoes in a large pan of salted cold water. Bring to a boil and cook for 8–10 minutes until the edges are soft but the centres still hold their shape.
Drain the potatoes thoroughly, then shake them gently in the colander to rough up the edges. This step is key for creating crisp, crunchy surfaces later.
Spread the potatoes on a tray and allow them to cool completely. Once cool, cover and refrigerate for up to 24 hours. This drying stage improves roasting results.
When ready to cook, preheat the oven to 200°C (400°F). Heat the oil or fat in a roasting tray until very hot.
Carefully add the potatoes to the hot tray, turning them to coat. Roast for 45–55 minutes, turning once or twice, until deeply golden and crisp all over.
Season generously with salt and pepper. Add herbs or garlic during the final 15 minutes if desired, then serve immediately.
Find it online: https://jamieolivereats.uk/make-ahead-potatoes/