4 sweet potatoes, scrubbed clean
Olive oil, optional
4 tbsp. butter
Freshly ground black pepper
Preheat oven to 425º. On a baking sheet lined with aluminum foil, prick sweet potatoes all over with a fork. Rub the outsides with a small amount of olive oil if you intend to eat the skins.
Bake until tender, 45 to 50 minutes.
Let cool, then split the tops open with a knife and top with a pat of butter.
Season with salt and pepper before serving.