Bring the potatoes to the boil in cold salted water and cook until tender and falling off the end of a knife.
Drain and cover with a clean tea towel to steam dry while you prep the oil. Mix all of the other ingredients together in a baking tray and spread it out evenly.
Cut the spuds in half lengthways for maximum crispy-ness and put face down flat into the oil and parmesan mix. Roast for 30-40 minutes at 180ºc/3500ºf until golden brown, crispy and delicious. Check them after 20 minutes as you may need to drain some oil from the tray if it ends up being too much.
