Preheat oven to 375 degrees.: The air in the oven will smell faintly warm and dry as it comes up to temperature, which primes the surface of the potatoes to crisp when they hit the sheet. This steady, moderate heat helps cook the interiors through without burning the exterior too quickly. A common mistake is skipping preheating, which can lead to soggy rather than crisp edges, so give the oven time to reach the full temperature.
Combine fresh herbs, salt, garlic powder, and Parmesan cheese in a small bowl. Set aside.: As you mix these aromatics, the fragrant blend releases herb oils and the salt begins to meld with the cheese, creating a cohesive seasoning. The scent should be herb forward and savory, signaling the flavor that will coat each piece. If you rush and skip mixing, you risk uneven distribution, so take a moment to combine thoroughly.
Place potatoes in a large bowl and drizzle with olive oil. Toss to coat.: When you toss the potatoes with olive oil , each surface should shine slightly, indicating an even coat. This step is crucial for heat transfer and browning, so ensure every piece is lightly covered. Overcrowding the bowl while tossing can lead to uneven oil coverage, so use a spacious container.
Sprinkle with the seasoning mixture, tossing to coat once again.: After adding the seasoning, smell the aromas lift off the bowl as the Parmesan cheese and herbs adhere to the oiled surfaces. Toss until the herbs and powder cling to the potatoes rather than sitting in lumps. A frequent error is dumping the seasoning and not tossing, which leaves pockets of intense flavor; even distribution is key.
Spread potatoes in a single layer on a baking sheet. Sprinkle on any seasoning left in the bowl.: Laying the potatoes in a single layer ensures air circulates and lets each piece develop a golden crust. Visually, you want space between them rather than tight clusters. If pieces are touching heavily, they will steam and lose crispness, so use two sheets if needed rather than crowding.
Bake for 20 to 30 minutes, depending on size, or until potatoes are tender.: During baking you will hear a light ticking sound as moisture leaves and the edges become crisp, and the aroma will turn deeply savory and toasty as the Parmesan browns. A visual cue is golden brown edges and a fork slipping into the center without resistance. The typical pitfall is checking too early; wait until the color develops and a knife slides in with slight resistance removed.
Serve immediately.: The moment you remove the tray, steam will rise and the surface will feel crisp to the touch, while the interior remains pillowy and creamy. Serving right away preserves that satisfying contrast between crunchy exterior and tender inside. Letting them sit too long will soften the crisp edges, so present them promptly for the best texture.
