1Steam/Boil Potatoes until fully cooked not par boiled.
2 While thats happening preheat the oven to maximum temp (mines 220°C) with a roasting tin with at least 1inch of vegetable oil. (You need to get everything SUPER hot. 10 mins preheating won't do here-you'll need at least 30min)
3When the potatoes are boiled &drained shake them a little or rub with a fork to rough up the surface. While they are still piping hot put them in the hot hot oil and baste.
4Get them back in the oven as quickly as possible so the temp of the oil doesn't drop.
5 Put the roasting tin on the shelf nearest the heating element of your oven.