Thyme and Parmesan roasted potatoes

Peel, chop, wash and dry potatoes well using kitchen roll. (Important or they don't go crispy.) Put in a roasting tray. Spray with olive oil, sprinkle with salt and thyme. When nearly done, after about 40 mins or so, take them out and grate over some Parmesan (good amount, as much as you fancy!) Give a mix. Finish off in the oven for 8-10 mins