Peel the potatoes and cut into small pieces. Cook in salted water until soft for about 20 minutes.
Heat the sausages in the pan in a little oil slowly and not too much, otherwise they may burst.
In the meantime, slowly heat the sauerkraut in the pot. Cut the onion, half an apple and two 5 mm thick pineapple slices into small pieces and fry lightly in oil in a pan. Mix with the sauerkraut and add sugar to taste.
When the potatoes are nice and soft, drain the water. Add the cream and mash the potatoes by hand. Season with salt, pepper and nutmeg.
Serve the bratwurst with mustard, sauerkraut and puree.