coarse kosher salt and freshly ground black pepper
Preheat the oven to 425°.
Wash and dry the potatoes then place them on a cutting board on their flattest side. Working one at a time place a potato between two chopsticks, this will prevent you from slicing all the way through. With a sharp knife, slice down from top until the knife makes contact with the chopsticks. Repeat the process creating thin slices all the way down the length of the potato. Do the same with the remaining potatoes.
Arrange the Hasselbacked potatoes on a baking sheet, drizzle with half the olive oil and season with a generous amount of salt and pepper. Roast for 20 minutes, then remove from the oven and brush with the other half of the olive oil and roast for an additional 20 minutes until the slices are fanning apart and crisp on the edges while the potatoes are tender in the middle.