Cut root vegetables such as carrots, celeriac, yellow carrots and parsley root into cubes and blanch in salted water, remove and cool in ice water. Quickly brown the beef joint in the pan, then put in the vegetable water and leave to simmer for around 1 hour, depending on size. Peel and cut the potatoes, then slowly boil in salted water with a dash of vinegar. Cut the Tropea onions into julienne strips, lightly brown in olive oil, caramelise with a little honey, slake with a little red wine and then pour soup over. Add mustard seeds and peperoncino sauce, reduce and season with the herbs. Remove the beef joint from the soup, cut into slices, toss the root vegetables and potatoes in butter, roll a few slices of Lardo in the onion Mostarda and arrange on plates.