Wash pre-boiled potatoes, take care to have them half cooked, so that slices of 2 or 3 cm can be easily cut from them.
Peel potatoes. Cut 2-3 cm long slices. In a non stick pan melt butter. When a little hot fry potatoes to golden brown taking care that they dont break.
Grate cheese. Beat cream lightly. Thinly cut cabbage after washing. Now add cheese to the already beaten cream. Mix in salt and pepper, mustard powder sauce and vinegar. Mix well.
Now on each potato slice put some cut cabbage, a spoon of this mixture. Place another fried potato slice on the top. Pierce with tooth pick.