Preheat oven to 400°F.
Wash and scrub the potatoes really well, as the skins stay on for this recipe. Dry the potatoes and place them in a large bowl. Then, pour the olive oil over them.
Line a half-sheet pan with extra-wide heavy duty aluminum foil and place an oven-proof half sheet rack inside. Rub the oil all over the potatoes and place them on the rack. Then, prick the potatoes all over with a fork.
Sprinkle Kosher salt over the potatoes in pinches, flip the potatoes over and sprinkle salt on the other side.2 Then, rub the salt into the potatoes, making sure to cover the entire surface. Bake in a 400°F oven for 50 minutes.
Remove the pan from the oven and place on a wire cooling rack. Allow the potatoes to cool for 10-15 minutes, or until you can handle them easily.
When you can easily handle the potatoes, slice them into large bite sized chunks. Then, place the chunks into a large 4-qt. bowl. While they are still warm, immediately pour the apple cider vinegar over them. Then, using your hands, gently toss the potatoes to make sure they are all coated in the vinegar. Allow the potatoes to sit for 30 minutes.
Place sour cream, mayonnaise, freshly ground black pepper, garlic powder, and remaining Kosher salt in a small bowl. Use a small whisk to combine the sauce. Pour the sauce over the cooled potatoes. Then, gently stir the sauce into the potatoes with a silicone spatula, making sure they are evenly coated.
Add the cooked and crumbled bacon, extra sharp cheddar cheese, and chopped green onions to the bowl. Then, gently stir them into the potatoes so they are evenly distributed. Cover the bowl with plastic wrap and refrigerate for at least three hours, but preferably overnight.
Before serving, top with additional bacon, cheese, and green onions.
Yield 12 servings