Adjust oven rack to lowest position, place rimmed baking sheet on rack and heat oven to 450°. Place potatoes and 1 tablespoon salt in Dutch oven; add cold water to cover by 1 inch. Bring to boil over high heat; reduce heat and gently simmer until exteriors of potatoes have softened but centers offer resistance when pierced with paring knife, about 5 minutes. Drain potatoes well and transfer to large bowl. Drizzle with 2 tablespoons olive oil and sprinkle with½ teaspoons salt; using rubber spatula, toss to combine. Drizzle with another 2 tablespoons oil and½ teaspoons salt; continue to toss until exteriors of potato slices are coated with starchy paste, 1 to 2 minutes.

Working quickly, remove baking sheet from oven and drizzle remaining tablespoon oil over surface. Carefully transfer potatoes to baking sheet and spread into even layer (skin-side up if end piece). Bake until bottoms of potatoes are golden brown and crisp, 15 to 25 minutes, rotating baking sheet after 10 minutes.

Remove baking sheet from oven and, using metal spatula and tongs, loosen potatoes from pan, carefully flipping each slice. Continue to roast until second side is golden and crisp, 10 to 20 minutes longer, rotating pan as needed to ensure potatoes brown evenly. Season with last and pepper to taste and serve immediately.