Prep the potatoes. Wash and dry thoroughly. Cut into evenly sized fries about 1/4–1/3 inch thick. Consistent size = even cooking.
Soak (optional but clutch). Place fries in cold water for 20–30 minutes to remove excess starch. Drain and pat very dry. Moisture is the enemy of crisp.
Preheat. For oven: set to 425–440°F (220–226°C) and preheat a sheet pan inside for 5–10 minutes. For air fryer: preheat to 380°F (193°C).
Coat with starch first. In a large bowl, toss dried fries with cornstarch/arrowroot until lightly coated and no visible powder clumps remain.
Add oil and spices. Drizzle oil, toss to coat. Add salt, pepper, smoked paprika, garlic powder, and optional heat. Toss again.
Oven method. Carefully spread fries on the hot sheet pan lined with parchment, leaving space between pieces. Bake 15 minutes, flip, then bake another 10–15 minutes until browned and crisp at the edges. Finish with 2–3 minutes under the broiler if needed. Season with flaky salt.
Air fryer method. Arrange fries in a single layer (work in batches). Air fry 12–15 minutes, shaking halfway, until crisp and golden. Adjust time based on thickness. Keep finished batches warm in a 200°F oven.
Finish strong. Sprinkle with chopped parsley, a squeeze of lime, and serve with your dip of choice.