Preheat oven to 450 degrees F (230 degrees C). Scrub and dry potatoes, then prick several times with a fork and place on a baking sheet.
Bake in preheated oven until potatoes are easily pierced with a fork, 50 minutes to 1 hour. Remove from oven and cool slightly.
Reduce oven to 350 degrees F (175 degrees C).
Cut a thin slice off the top of each potato; scoop out pulp and place in a small bowl. Beat potato flesh, butter, milk, and salt with an electric mixer in a large bowl until smooth and fluffy. Fold cream cheese and sour cream into potatoes; spoon mixture into potato shells. Sprinkle with paprika and place on a baking sheet.
Bake in preheated oven until heated through and tops are golden brown, 20 to 25 minutes.