Preheat the oven: Heat to 425°F (220°C) with a rack in the center position.
Prepare the potatoes: Scrub the sweet potatoes clean and dry them thoroughly. Prick each potato 8–10 times with a fork.
Season: Rub each potato with the olive oil, then sprinkle evenly with the kosher salt.
Arrange for roasting: Place the potatoes directly on a wire rack set over a sheet pan (or directly on a foil-lined sheet pan). Do not wrap them in foil.
Roast: Bake for 60–75 minutes, until a knife slides through with no resistance and the skin is deeply caramelized and slightly crisp. Some sugary juices may bubble out near the end - this is expected.
Rest and serve: Let rest for 5 minutes. Slice lengthwise, fluff the interior with a fork, and serve with flaky salt and your favorite toppings.
Notes
Thoroughly drying the potatoes before oiling helps the skin crisp.
Pricking the potatoes allows steam to escape and helps prevent splitting.
A wire rack promotes even airflow and crispier skin, but a sheet pan works well too.
Great finishing toppings include:
Brown butter or miso butter
Honey or maple syrup
Crème fraîche or labneh
Toasted nuts or seeds
For an even richer finish, brush the skins with melted butter about 45 minutes into roasting.
For extra blistered, crispy skin, broil for 2–3 minutes after roasting