
Drain your potatoes and return to the pan, with the lid on, toss them in the pan a few times, then add your flour, salt, pepper and rosemary (if using dried). Toss again to combine.
Preheat your oven to 190°c. While the oven preheats, add your 3 tbsp of neutral cooking oil to your roasting dish and place that in the oven to preheat the oil.