Preheat the oven to 425°F (220°C).
Scrub the potatoes thoroughly under running water and pat them dry.
Prick each potato 4–6 times with a fork to allow steam to escape while baking.
Rub each potato with a thin layer of olive oil so the skin crisps during baking.
Sprinkle coarse salt over the skins to taste for added flavor and texture.
Place the potatoes directly on the oven rack or on a foil-lined baking sheet.
Bake 50–60 minutes for medium potatoes or 60–75 minutes for large potatoes, until a skewer slides in easily.
Remove potatoes from the oven and let them rest for about 5 minutes to finish cooking.
Slice each potato open lengthwise and push the ends toward each other to fluff the interior.
Top with butter, salt, pepper and any desired toppings such as sour cream, cheese, chives, or bacon bits, then serve.