Preheat the oven to 450 degrees F.
In a large bowl, combine the olive oil, balsamic, salt, rosemary and some pepper. Toss the potato wedges with the mixture and spread them in one layer evenly onto two baking sheets.
Roast the potatoes, turning over once, until golden brown and cooked through, about 20 minutes. Sprinkle with the Parmesan and serve immediately.