Preheat the oven to 200°C (180°C fan)/400°F/gas 6.
Place the potatoes between the handles of 2 wooden spoons
and cut them at 2mm intervals until the knife hits the
handles, so you don’t slice them all the way through.
Pop the
potatoes onto a roasting tray. Drizzle over the butter and oil,
sprinkle over the rosemary and season. Roast in the oven for
45 minutes–1 hour.
Serve with fish, lamb chops or chicken breast.