Drain the pineapple and collect the juice. Cut the rings into pieces. Place in a pot with sauerkraut, 2 tbsp. pineapple juice, allspice and bay leaf. Simmer covered for 20-30 minutes, then keep warm in a closed pot.
Peel and wash the potatoes and sweet potatoes, cut them into pieces and cook them in boiling, slightly salted water for 15-20 minutes. Wash the meat, dab dry, cut the skin several times. Heat a pan without fat.
First roast the duck breast on the skin side for 4-5 minutes, then continue roasting on the meat side for about 1 minute. Season the meat with salt and pepper and place on a baking tray. Cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 8 minutes in medium heat.
2-3 minutes before the end of the cooking time, brush the meat with honey on the skin side. Remove the meat, wrap it in aluminium foil and let it rest for about 5 minutes in a warm place. Drain the finished potatoes, collect the cooking water, measure approx. 125 ml, add to the potatoes again.
Add butter, mash to puree. Season to taste with salt, pepper and a little sugar. Wash the marjoram, dab dry, pluck leaves from the stalks. Coarsely chop the leaves, mix into the sauerkraut and season with salt and pepper.
Wrap meat out of the foil, cut into slices, arrange with puree and sauerkraut.