Preheat your oven to 400°F (200°C).
Wash and scrub the baking potatoes thoroughly. Pat them dry and prick them with a fork a few times to allow steam to escape during baking.
Rub the potatoes with oil and sprinkle with salt. Place them directly on the oven rack or on a baking sheet. Bake for about 45-60 minutes, or until they're tender when pierced with a fork.
Remove the potatoes from the oven and let them cool slightly so you can handle them.
Cut each potato in half lengthwise. Carefully scoop out the insides, leaving a thin shell to hold the filling.
In a mixing bowl, mash the potato insides with a fork or potato masher. Add the sour cream, milk, butter, half of the crumbled bacon, half of the shredded cheddar cheese, half of the chopped scallions, salt, and pepper. Mix well until the ingredients are combined and the mixture is creamy.
Spoon the potato mixture back into the potato shells, mounding it slightly.
Top each potato with the remaining shredded cheddar cheese and crumbled bacon.
Place the potatoes back in the oven and bake for an additional 15-20 minutes, or until the cheese is melted and bubbly.
Remove the potatoes from the oven and sprinkle with the remaining chopped scallions.
Let the potatoes cool for a few minutes before serving.