Preheat oven to 200°C (180°C fan-forced) and line 2 oven trays with baking paper.
Place the whole potatoes in a large pot of water. Bring to the boil and simmer for ten minutes until they're just soft. This gives the potato wedges a crust on the outside while being soft on the inside. You can skip this step but you may need to cook the potatoes a little longer.
Cut the potatoes in half lengthwise, and then into thirds or quarters, depending on how big the potatoes are.
Toss the potatoes in olive oil.
Add the parmesan cheese, chopped rosemary, salt and pepper.
Spread out the potatoes evenly on the two trays, then cook for about 40 minutes until brown on the edges and cripsy. If they're ready before your main dish is done, turn off the oven, and let them rest.
If you like, shave a little black truffle on top.