Heat the oven to 400 °F. The potatoes will bake more evenly once the oven is fully hot.

Set the cleaned potatoes on a baking sheet, pierce each one 4-5 times with a fork, rub lightly with olive oil, and sprinkle with kosher salt. Bake for 50-60 minutes, until the skins look dry and crisp and a skewer slides into the center with no resistance.

Let the potatoes rest for 5 minutes, then peel them while they are still warm and cut them into 1-inch chunks into a large mixing bowl. Some pieces will look crumbly and shaggy instead of perfectly neat, and that texture is exactly right for a creamy salad.

Sprinkle the warm potatoes with the apple cider vinegar and leave them alone until cooled. The potatoes will absorb the vinegar as the steam fades, which builds flavor all the way through.

While the potatoes cool, cook the bacon in a large skillet or in the oven, then drain, cool, and chop it into bite-size pieces. The bacon should be crisp enough to break into chunks without turning hard or bitter.

Stir the mayonnaise, sour cream, kosher salt, and black pepper together in a small bowl. The dressing should look smooth, thick, and easy to spoon over the potatoes.

Add the dressing to the cooled potatoes along with the bacon, green onions, and cheddar cheese, then fold gently to combine. Mix just until coated so the potatoes keep some shape and the salad stays creamy instead of pasty.

Season to taste, then refrigerate for 3 hours up to overnight before serving. Once chilled, the dressing thickens and the onion, bacon, and cheddar flavors settle into the potatoes.