Roasted Potatoes Potatoes Olive oil Salt Fresh rosemary (optional) Preheat oven to 200 C. If using large potatoes, cut them into chunks. Put potatoes in a pot of salted water and bring to the boil. Parboil for 15 minutes. Drain in a colander and shake excess water off. Let stand for 10 minutes. Put oil in a oven dish, then add potatoes. Crush rosemary leaves and sprinkle on top. Roast for 20 minutes, turn the potatoes, then roast for a further 20 minutes.