4 russet potatoes (about 2½ pounds), scrubbed
Olive oil (for rubbing)
Flaky sea salt
Freshly ground black pepper
Unsalted butter, finely grated Parmesan (or your favorite cheese), and/or chopped fresh chives (for serving)
Preheat oven to 350°. Prick potatoes all over with a fork and rub with oil; season generously with salt and pepper.
Place potatoes directly on an oven rack and roast until very soft when squeezed and skin is crisp, 60–75 minutes.
Cut open each potato; season with salt and pepper and top with butter, Parmesan, and/or chives.