Preheat your oven to a blazing 425°F (220°C).
Wash the russet potatoes thoroughly to remove any dirt. Dry them completely with a clean kitchen towel. (Moisture prevents the skin from crisping).
Optional: Prick each potato 3 to 4 times with a fork to allow steam to escape during baking.
Rub each potato generously with the olive oil, ensuring the entire surface is coated.
Season the oiled potatoes heavily with the kosher salt and freshly ground black pepper, massaging the spices slightly into the skin.
Place the seasoned potatoes into a cast-iron skillet, leaving a little bit of space between each potato so the hot air can circulate.
Bake in the preheated oven for approximately 45–60 minutes, depending on the size of the potatoes. Use tongs to turn the potatoes over halfway through the baking time for even browning.
The potatoes are done when the skins are crisp and a fork slides easily into the very center with no resistance.
Carefully remove the skillet from the oven and let the potatoes rest for 5 minutes.
Slice the potatoes open, fluff the interiors with a fork, and serve hot with butter, sour cream, cheese, and fresh chives.