You can't go wrong with this classic flavor pairing.
In a small bowl, stir together sour cream and cheese; season with salt and pepper. Set aside.
Preheat oven to 350 degrees. On a large rimmed baking sheet, rub potatoes with oil. Bake on upper rack until tender, about 65 minutes.
To serve, cut a deep cross in each potato; push ends together to open. Season with salt and pepper; top with sour-cream mixture, and if desired, scallions.