Melt the butter in a large pan, sprinkle powdered sugar on the butter. Toss the vegetables in the butter and sugar, remove.
Fry the roast in the butter on all sides until it is nice and brown all over. Salt and pepper, sprinkle with a little caraway seeds. Return the vegetables. Cover the roast with a good dash of sherry. Put a tall lid on the pan and let it fry for an hour and a half over the lowest possible heat. Lift the lid as seldom as possible. Just make sure that the sherry sauce simmered really lightly in the pan. After an hour and a half, pour a little more sherry over the top. Remove the roast, wrap it in foil and let it rest.
In the meantime, pour off the sauce, sieve it and, if necessary, bind it with a little Mondamin and cold butter. Do not use cream.
The roasting time depends on the thickness of the roast; if the piece of meat is very thick, leave the roast in the pan for two hours.