Cut the potatoes. Scrub the potatoes well, then slice each potato lengthwise into 1/4-inch planks. Cut each plank into 1/4-inch sticks so the fries cook evenly.
Soak for better crunch. Place the potato sticks in a bowl of cold water and soak for 20 minutes. This helps remove extra surface starch so the fries crisp up instead of turning soft.
Dry very well. Drain the potatoes, then spread them on a clean towel. Pat until they feel dry to the touch.
Season evenly. Add the dry potato sticks to a large bowl. Toss with oil, cornstarch, garlic powder, onion powder, smoked paprika, salt, and black pepper.
Preheat the air fryer. Set the air fryer to 380°F for 3 minutes. While it heats, separate any fries that are sticking together.
Cook the first round. Arrange the fries in a single layer in the air fryer basket. Cook at 380°F for 10 minutes.
Flip and finish cooking. Shake the basket and flip the fries. Cook for another 6–8 minutes, or until golden and crisp.
Add parsley (optional). If using, sprinkle chopped parsley over fries after cooking.
Let rest and serve. Transfer fries to a serving dish and let stand for 2 minutes before enjoying.