Twice-roasted potatoes

Method

1. Prick the potatoes here and there 2-3 times with the point of a knife. Cook next to the lamb, directly on the oven rack, for 15 minutes at 230°C/ 210°C fan/gas 8, then for 50 minutes at 180°C/160°C fan/gas 4 until tender when pierced with a skewer.
2. Remove the potatoes from the oven then, as soon as you can handle them (an oven glove helps), cut each one into quarters. Lightly oil a roasting tin, then gently pinch each piece to open up the now fluffy potato. Put the pieces skin-side down in the tin. Drizzle the rest of the oil over the potatoes and sprinkle with a little salt and black pepper.
3. Return to the oven on the top shelf and roast at 200°C/180°C fan/gas 6 for 30-45 minutes until crisp and golden.