Start with baking potatoes (russets). Cut each peeled potato in half lengthwise, halve again, and slice each quarter into ¼-inch-thick strips (a mandoline is nice but not essential). Soak in cold water for 30 mins, then dry thoroughly with paper towels. Toss with olive oil, then spread on parchment-lined baking sheet. Don't overcrowd. Bake on bottom rack at 400° for 35 mins. Flip once halfway through.