Preheat your oven to 400 degrees Fahrenheit.

Wash and dry the potatoes, then prick them all over with a fork. Place the potatoes on a baking sheet and bake for 45-60 minutes, or until they are tender when pierced with a fork.

When the potatoes are cool enough to handle, carefully cut them in half lengthwise and scoop out the flesh, leaving a small rim of potato around the edges.

In a medium-sized bowl, mash the potato flesh together with the sour cream, milk, cheese, butter, salt, and pepper until smooth and creamy.

Spoon the mixture back into the potato skins and smooth the tops. Place the potatoes on the baking sheet and bake for an additional 20-25 minutes, or until the tops are golden and crispy.