Step 1

Heat the oven. Arrange 2 racks to divide the oven into thirds. Place a baking sheet on the lower rack to catch any drippings and heat the oven to 425ºF.

Step 2

Prep the potatoes. Scrub and dry 4 small russet potatoes. Rub 2 teaspoons olive oil on the potatoes and sprinkle all over with 1 teaspoon kosher salt.

Step 3

Bake the potatoes. Place the potatoes directly on the upper rack. Bake until tender, about 50 minutes. Meanwhile, prepare the toppings.

Step 4

Prepare the toppings. Grate 3 ounces sharp cheddar cheese on the large holes of a box grater (about 3/4 packed cup). Thinly slice the greens from 2 medium scallions. Cut 4 ounces bacon into 1/2-inch pieces.

Step 5

Cook the bacon and reserve the fat. Place the bacon in a medium skillet and cook on medium heat, stirring occasionally, until browned and crisp, 8 to 10 minutes. Transfer with a slotted spoon to a paper towel-lined plate. Keep the bacon fat in the skillet.

Step 6

Scoop out the potatoes. When the potatoes are ready, remove the baking sheet from the oven and set aside to cool. Transfer the potatoes to a wire rack and let sit until cool enough to handle but still warm, about 15 minutes. Cut each potato in half lengthwise. Scoop out the insides, leaving about 1/4-inch of potato as the shell, and transfer the insides to a bowl. Reserve the scooped-out flesh for another use.

Step 7

Heat the oven to broil. Wash and dry the baking sheet, then line it with parchment paper if desired. Place the potato shells on the baking sheet and brush the reserved bacon fat all over the flesh and skin sides. Arrange in a single layer skin-side down. Season with 1/4 teaspoon black pepper. Divide the cheese between the skins.

Step 8

Bake and assemble the potato skins. Bake on the upper rack until the cheese is melted, 1 to 2 minutes. Remove from the oven. Divide 1/3 cup sour cream, the bacon, and scallions between the potato skins and serve immediately.