How to Make It
Preheat the oven to 450°. Soak the potato slices in cold water for 5 minutes. Drain the slices and pat dry with paper towels.
Transfer the potatoes to 2 large, rimmed baking sheets and toss each batch with 1 tablespoon of the olive oil. Arrange the slices on the sheets side by side without overlapping and season with salt and pepper. Bake for 8 minutes, or until the potatoes begin to turn golden brown; as they brown, transfer the potato chips to a rack with a spatula.
Reduce the oven temperature to 350°. In a bowl, mix the shredded cheeses, then divide among individual gratin dishes. Bake the cheese for about 7 minutes, or until bubbling. Drizzle with truffle oil and serve at once with the potato chips.