puffed potatoes

Soufflé potatoes. But if you look that up to watch in YouTube you'll get results of regular soufflés made with potatoes as well because they're both potatoes and they're both puffed.

Potato trimmed into a rectangular block which makes peeling much easier, except if your potato has a hump like a camel then leave it because a potato hump is useful on the mandolin to protect your fingers or for the safety slider's prongs to have a hump to dig into. On my little green plastic Japanese mandolin there is a screw on the bottom to adjust the thickness of the slice. It's opened far as it goes and that makes pretty much the perfect width slice.

Like French Fries, it's a two-part frying process. Shallow fried in oil. 

The slices are cooked in oil at low heat to cook through. They begin to bulge with a bubble inside. They're removed from the oil as they begin to bulge. The oil is agitated throughout. The pot is swirled so the potatoes do not stick together and keep oil flowing over their tops. It causes the slice exteriors to begin forming a protective shell while the interiors cook and the moisture inside release steam that is trapped by the tougher exterior. So the slices must cook on low long enough for the potato slice interiors to cook. If the oil is too high then they'll form into chips instead. Low for oil is still hotter than boiling water.

The oil is turned up to dehydrating frying temperature, they puff immediately and become crisp like two potato chips connected around the edges. They crisp in the form of a hollow pillow. 

Oil under 300℉ to start

Oil at or over 350℉ to finish.

Some cooks use two pots of oil.