photo by William AbranowiczyieldMakes 8 servings Cooking the potatoes on a wire rack lets hot air circulate around them, so they get extra crisp.
Place a rack in upper third of oven; preheat to 400°F. Toss potatoes and oil in a large bowl; season with salt and pepper. Place potatoes, cut side up, on a wire rack set inside a rimmed baking sheet; reserve bowl. Roast until golden brown and cooked through, 30–35 minutes. Transfer to bowl; toss with Parmesan. Return potatoes to rack and roast until Parmesan is brown and crisp, 10–12 minutes.
Toss potatoes in same bowl with parsley, lemon juice, and red pepper flakes. Top with lemon zest just before serving.