Preheat oven to 375 degrees F. Scrub and wash each potato and dry thoroughly. Poke each potato several times with a fork and wrap each potato in foil. Bake the potatoes for 45-60 minutes (time will vary depending on size and oven). Remove from oven and allow time to cool.
Prepare the filling- in a medium mixing bowl, mix together the chopped corned beef, sauerkraut and Thousand Island dressing. Set aside or store in an airtight container in the refrigerator for later use.
When the potatoes are cool enough to handle, cut each potato lengthwise and carefully scoop out the inner flesh, making sure to leave behind a thin layer. Meanwhile, preheat oven to 400 degrees F and line a baking sheet with parchment paper.
Fill each halved potato skin with filling, sprinkle with fresh ground black pepper and cover the top with a half slice of swiss cheese.
Transfer potatoes to a lined baking sheet and bake at 400 degrees for approximately 15 minutes, or until cheese is melted and bubbly. Remove potato skins from the oven and sprinkle with fresh chopped parsley and additional dressing, if desired.
Delicious just out of the oven or leftover the next day