1) Preheat oven to 220C/Gas 8.
2) Cut each potato, lengthwise, into 8 wedges. Trim all but 0.5cm of the potato flesh with a pairing knife.
3) Lay the skins on a baking sheet, skin side down , and spray the flesh side with the olive oil spray. Season with salt and pepper, to taste. Roast until golden and crispy, about 35 minutes.
4) Meanwhile, puree the cottage cheese, sour cream, and horseradish in a blender. Transfer to a small serving bowl and season with salt and pepper, to taste. Sprinkle chives on top.
5) Put hot potato wedges on a platter with the bowl of horseradish cream. Serve.