Position 2 racks in the center of the oven and preheat to 375 degrees F. Wash and dry the potatoes, then prick each all over 8 to 10 times with a fork. Rub the butter evenly on the potatoes, and sprinkle generously with salt and pepper. Place the potatoes on a baking sheet with at least 1 inch of space between them.

Put the bacon in a single layer on a rimmed baking sheet lined with parchment paper.

Place both baking sheets in the oven, the bacon below the potatoes. Cook the bacon, flipping halfway through, until golden brown and crispy, 18 to 25 minutes (or possibly longer, it depends on how thick the bacon is.); transfer to a paper-towel-lined plate, let cool and then crumble. Continue baking the potatoes, flipping halfway through, until the skin is crispy and the potatoes are fork-tender, 45 to 50 minutes. Transfer the potatoes to a cutting board and let cool completely. You can place in the fridge to speed up the process. Quarter each cooled potato lengthwise, then cut into 1-inch pieces.

In a large bowl, whisk together the sour cream, mayonnaise, apple cider vinegar, 2 tablespoons water and 1 teaspoon each salt and pepper. Add the potatoes, bacon, shredded cheddar cheese and white parts of the green onions, and gently stir to combine. (Reserve some of the bacon and cheese to garnish the potato salad.) Season with additional salt and pepper if needed.

Serve immediately or refrigerate until ready to serve. Garnish with the remaining green onions, shredded cheese, and crumbled bacon, right before serving.

Enjoy!