Crispy parmesan and oregano roasties

Method

1. Heat the oven to 200°C/180°C fan/gas 6. Put the potatoes in a large pan of boiling, salted water and cook for 7-8 minutes until not quite cooked – they should still be quite firm when pierced with the tip of a sharp knife. Drain well.
2. Meanwhile, drizzle the oil into 1-2 large (preferably non-stick) roasting tins (the potatoes need enough room to fit in a single layer) and evenly grate over the parmesan to cover the base(s) – the fine side of a box grater is best. Evenly scatter over the mustard powder, cayenne and oregano. Arrange the potatoes, cut-side down, on top of the cheese. Brush the potatoes with a little more oil and season well with salt. Roast in the oven for 45-50 minutes until the parmesan is golden and crisp and the potatoes have shrunk slightly and are crisp and tender. 
3. Remove the potatoes from the tin(s) using a palette knife or fish slice and transfer to a serving dish, making sure you scrape up all the crispy browned bits of parmesan from the base. Serve straightaway.