Ingredients
Method
- Preheat the air fryer to 400 degrees F for 3-5 minutes. A cold basket lets the cubes sweat instead of browning.
- Scrub the sweet potatoes and cut them into 1-inch cubes, keeping them as even as possible. Peeling is optional and doesn't change the cook time. Pat the cubes dry with a towel.
- Toss the cubes with the oil first, until every piece is lightly coated. Then add the cornstarch, salt, garlic powder, smoked paprika, and black pepper and toss again. The oil gives the seasoning something to cling to.
- Arrange in the basket in a single layer with space between the cubes. Cook in two batches if they don't all fit.
- Air fry 12-15 minutes, shaking the basket halfway through. They're done when the edges are deep golden and a fork slides in easily.
- Serve immediately, adding a pinch more salt if they taste flat.
Notes
Cut them a full inch. Half-inch cubes are mostly surface area, so they dry into something leathery before the middle turns creamy.
Don't soak them. That advice comes from regular potatoes, which have a lot of surface starch worth removing. Sweet potatoes have less starch and more moisture, so soaking mainly adds water you then have to cook off.
The cornstarch is the crisping trick. Sweet potatoes are low in starch, so a light dusting supplies what they lack and forms a thin shell that goes crisp and stays crisp. You can't taste it.
Sweet potatoes have a lot of sugar, so they can go from caramelized to scorched quickly. If your air fryer runs hot, drop to 375-380 degrees F and add a couple of minutes rather than pushing the heat.
Use garlic powder rather than fresh garlic, which burns before the potatoes are tender.
Square off the potato before cubing. They taper, so slicing straight across gives wildly uneven pieces without you noticing.
Cool completely before storing. Sealing them warm traps steam and softens them. Keeps 5 days in the fridge; reheat at 350 degrees F for 2-4 minutes.
For a sweet version, swap the garlic and paprika for 1/2 tsp cinnamon and drop to 375 degrees F, since cinnamon scorches easily.
Frozen cubes work straight from the freezer; add 4-6 minutes.