Preheat oven to 200°C (400°F), or air fryer to 190°C (375°F). Toss the halved potatoes with olive oil, dried thyme and rosemary, salt, and pepper, then spread evenly on a baking tray. Roast for 25–30 minutes, turning halfway, until golden and crisp. If using an air fryer, cook for 18–20 minutes, shaking the basket halfway through, until golden and crunchy on the edges.