Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper.
Slice the cleaned potatoes into approximately ⅛-inch-thick rounds, keeping the slices as even as possible.
Place the potato slices in a bowl and toss them thoroughly with the olive oil until lightly coated.
Add the finely grated Parmesan cheese and chopped fresh rosemary. Toss gently until the ingredients are distributed evenly.
Arrange the potato slices in a single layer on the prepared baking sheet, leaving a little space between each piece.
Bake for 18–25 minutes, turning the slices once halfway through, until they are golden brown and crisp around the edges.
Remove the crisps from the oven and let them rest for 2–3 minutes so they can firm up.
Transfer to a serving dish and enjoy warm.
