Perfect roast potatoes

Preheat the oven to 180°C.Using a sharp knife, peel the potatoes.Cut the potatoes in half, lengthways.Place into a large saucepan. Add water to just cover and sprinkle with salt. Parboil for 7 to 10 minutes or until about three quarters cooked – take care not to overcook the potatoes or they will turn to mash. Drain in a colander and cool for 10 minutes.Return to the dry saucepan and shake vigorously to roughen the outsides.Finely chop the garlic and rosemary and sprinkle over the potatoes before tossing in the onion sprinkles and duck fat.Lay flat in a baking dish, ensuring there is enough space between them for a golden crust to form. Roast for 45 minutes, or longer if you prefer your potatoes quite brown. Season and serve immediately.