Preheat a heavy, rimmed baking sheet in the oven to 450.
Cover the potatoes by one inch of water in a dutch oven, then bring to a boil over high heat. Reduce heat and simmer until the potatoes are undercooked in the middle, then drain, then toss with olive oil and salt until the potato exteriors are covered with a starchy paste.
Coat the baking sheet with olive oil, then roast the potatoes on the baking sheet, turning once to brown and crisp both sides.