If you can’t find new potatoes at the farmers’ market, look for Peewee potatoes or very small Yukon Golds at the grocery store.
- 1 pound new or other small waxy potatoes, halved if large
- Kosher salt, freshly ground pepper
- 1 ounce finely grated Parmesan (about 1 cup), divided
Preheat oven to 425°. Drizzle potatoes with oil on a large rimmed baking sheet and toss to coat; season with salt and pepper. Roast, tossing once, until golden brown and tender, 20–25 minutes. Remove potatoes from oven and scatter half of Parmesan over top. Roast until cheese is melted, about 1 minute. Remove from oven and toss just to evenly coat potatoes.
Transfer potatoes to a platter and top with remaining Parmesan; season with pepper. Spoon dressing over top.