Preheat the oven to 350 degrees F.

Using a box grater, grate the potatoes onto a large kitchen towel. When finished, spread the grated potatoes out on the kitchen town and roll it tightly. Over the sink, squeeze as much liquid out of the potatoes as possible. (Note: This is the most critical step to crispy potatoes. Squeeze the heck out of those potatoes and don't stop until they are super dry.)

Transfer the potatoes to a mixing bowl and toss with salt and pepper.

Heat an 8-inch oven-safe skillet over medium-high heat. When hot, add the butter, and swirl to coat the bottom of the skillet. Add the grated potatoes to the hot pan, gently spreading them out to evenly cover the bottom of pan. (Note: Resist the urge to press the potatoes into the pan. Leave them light and textured - this will make for more surface area to crisp up in the oven). Cook until you can lift the potatoes gently with a spatula and see that the bottom of the potatoes are golden brown and crisp, about 5-8 minutes.

Carefully transfer the hot pan to the oven and cook until the potatoes are cooked through, 10-15 minutes. Finally, turn on the broiler, and blast the surface of the potatoes until golden brown and crisp, about 2 minutes more.

Slice into wedges and serve.