Mandoline-cut sweet potatoes fried in rendered duck fat then sprinkled with coarse salt and freshly-ground pepper..
Wash and peel as many sweet potatoes (garnet yams) as you intend to fry. Using a mandoline set to about 1/16″, slice potatoes on a bias directly into a bowl of ice water. Allow potatoes to sit in ice water for 1 hour, then spread out on clean kitchen towels and pat completely dry.
Heat rendered duck fat (substitute beef tallow) in a scrupulously-clean skillet to a depth of about 1/2 inch until it shimmers. On my electric stove, I set the dial to mark below medium. If the oil is smoking, the pan is too hot.
Place sliced potatoes into hot oil and fry, turning once, until golden brown, about 1 1/2 minutes per side. Work in batches so as not to crowd the pan. Transfer to kitchen towels to drain and season immediately with coarse sea salt and freshly-ground pepper. These chips are best served still hot, but still great at room temperature.