Preheat the oven to 200C/Gas Mark 6. Place the potatoes in a small saucepan and cover with cold salted water. Bring to the boil on a high heat. Boil for 10 minutes, then drain. Meanwhile, put the oil in a baking dish and place in the oven. Put the drained potatoes in the hot oil, season with salt and bake in the oven for 30 minutes, tossing in the oil after 15 minutes.