Preheat the oven to 400 degrees . Pierce the potatoes with a fork; brush with oil. Bake until tender, 1 hour. Let cool, then cut into bite-size pieces.
In a skillet, cook the bacon until crisp, about 10 minutes. Drain.
In a large bowl, combine the butter and sour cream; season with salt and pepper. Stir in the potatoes, bacon, scallions and cheese. Serve at room temperature.