Wash the meat bones in a cool place, put them in a saucepan, pour 2 liters of cold water, add a few peppercorns and let it boil. Add the rinsed meat to the boiling clear soup and simmer gently for about 1/2 hour. Keep on skimming. Halve the onion with the skin, fry it on the cut surface in a frying pan and add it to the clear soup. Add the soup vegetables and garlic, continue cooking for another half hour. Remove the softly cooked meat, strain the clear soup and cool the meat in the clear soup.
Then cut into 1 cm thick slices and season with salt and pepper. Mix the mustard with the shallot and freshly grated horseradish and coat the meat on both sides.
Dust with flour and fry in a frying pan with clarified butter until golden brown on both sides.
As a side dish, fried potatoes and Vogerlsalat go very well.
By the way: Did you know that clarified butter is obtained by extracting water, milk protein and lactose from butter?