Prep the potatoes: Wash, peel if you like, and cut into fries about 1/4–1/3 inch thick.
Try to keep them similar in size for even cooking.
Soak for crispness: Place the fries in a bowl of cold water and soak for 20–30 minutes. This pulls off excess starch and helps them crisp instead of steam.
Dry thoroughly: Drain and pat the fries very dry with a clean towel. Moisture is the enemy of crunch.
Season the coating: In a large bowl, mix oil, minced garlic, chopped fresh chilli (or flakes), chilli powder/paprika, cumin, salt, and pepper.
If using cornstarch, sprinkle it in and whisk to combine. The mixture should be slightly thick, not pasty.
Toss the fries: Add the dry fries to the bowl and toss until everything is evenly coated. Make sure the garlic is distributed so it doesn’t clump.
Preheat the air fryer: Heat to 380°F (193°C) for 3–5 minutes.
A hot basket helps immediate crisping.
Arrange and cook: Spread fries in a single layer. Don’t overcrowd; cook in batches if needed. Air fry at 380°F (193°C) for 12–15 minutes, shaking the basket or flipping halfway.
For extra color, bump to 400°F (204°C) for the last 2–3 minutes.
Check doneness: Fries should be golden with crisp edges and tender centers. Add 2–4 more minutes if they need it, shaking again.
Finish and serve: Transfer to a bowl, squeeze over fresh lime, and toss with chopped cilantro or parsley. Taste and add a pinch more salt if needed.
Serve hot with your favorite dips.