Preheat the air fryer: Preheat your air fryer to 200°C / 392°F for 3–5 minutes. A preheated basket starts crisping the potatoes on contact — do not skip this.
Cut and dry the potatoes: Wash 4 medium potatoes — Russet, Maris Piper, or Yukon Gold and cut into evenly sized cubes — approximately 2.5cm (1 inch). Smaller cubes give extra crispiness; larger cubes give a fluffier centre. Peel or leave skin on — both work. Pat the cubes completely dry with paper towels before seasoning. Any surface moisture prevents crisping.
Season: Place the dried potato cubes in a large bowl. Add 2 pinch salt, 0.3 teaspoons paprika — smoked or sweet, 0.3 teaspoons black pepper, and 0.3 teaspoons garlic powder. Toss well until every piece is evenly coated.
Add cornstarch and oil: Sprinkle 1 tablespoons cornstarch (corn flour) — essential for the crispy crust over the seasoned potatoes. Add 1 tablespoons sunflower oil or any neutral vegetable oil and 2 pinch dried oregano. Toss thoroughly until every cube has a light, even coating with no dry white patches and no clumps. The cornstarch and oil together create the crispy crust — make sure every piece is covered.
Air fry: Arrange the coated potato cubes in the preheated basket in a single layer with a little space between each piece. Do not stack or overcrowd — cook in two batches if needed. Air fry at 200°C / 392°F for 25–30 minutes.
Shake halfway: At the 15-minute mark, shake the basket or gently stir the potatoes to ensure all sides brown evenly. Return to the air fryer for the remaining time.
Check and serve: At 25 minutes, check one cube — the outside should be deep golden and crispy, the inside soft when pierced with a fork. For a deeper color, cook for a further 5 minutes. Serve immediately — air fryer roast potatoes are at their crispiest in the first 10 minutes out of the basket.