Cook the peeled potatoes in salted water with the stock cube as usual.
In the meantime, peel the onions, dice them finely and sauté them in the frying fat until translucent. Then add the cucumber water, the beetroot liquid and the cut corned beef and let simmer on a low flame. Do not sear it!
Drain the potatoes and save some of the cooking water. Then mash the potatoes and mix them with the meat mixture. Season to taste with salt, pepper and nutmeg. If the mixture is too firm, add a little potato water.
Fried eggs, pickled cucumber, beetroot and sweet and sour pumpkin are enough as a side dish.