Twice Baked Potatoes from Cook's Illustrated Magazine

4 russet potatoes (7 to 8 ounces each), scrubbed, dried, and rubbed lightly with vegetable oil

4 ounces sharp cheddar cheese, shredded (about 1 cup)
1/2 cup sour cream
1/2 cup buttermilk
2 tablespoons unsalted butter, room temperature
3 medium scallions, white and green parts sliced thin (about 1/2 cup)
1/2 teaspoon salt
Ground black pepper
1. Adjust oven rack to upper-middle position and heat oven to 400 degrees. Bake potatoes on foil-lined baking sheet until skin is crisp and deep brown and a skewer easily pierces flesh, about 1 hour. Setting baking sheet aside, transfer potatoes to wire rack and let sit until cool enough to handle, about 10 minutes.

2. Using an oven mitt or folded kitchen towel to handle hot potatoes, cut each potato in half so that blunt sides will rest on work surface. Using a small dinner spoon, scoop flesh from each half into medium bowl, leaving 1/8- to 1/4-inch thickness of flesh in each shell. Arrange shells on lined sheet and return to oven until dry and slightly crisped, about 10 minutes. Meanwhile, mash potato flesh with fork until smooth. Stir in remaining ingredients, including ground black pepper to taste, until well combined.

3. Remove shells from oven and increase oven setting to broil. Holding shells steady on pan with oven mitt or towel, spoon mixture into crisped shells, mounding slightly at the center, and return to oven.I topped with extra cheese and bacon.
Broil until spotty brown and crisp on top, 10 to 15 minutes. Allow to cool for 10 minutes. Serve warm.