Prepare the vegetable broth by placing the onion, carrot and celery into a large pot (whole or roughly chopped) together with the herbs and spices.Bring to a boil, reduce the heat and simmer for about 20 minutes.Lower the tied beef into the boiling broth (Photo 1). Cook until tender, about 50 minutes (Photo 2), removing any foam that forms on the surface.Transfer the cooked beef to a sheet of aluminum foil, wrap it well and allow it to cool completely.Reserve about one cup of the cooking broth for the sauce.
Vitello Tonnato Sauce
Drain the tuna completely and place it into a blender (Photo 3).Add the capers (Photo 4).Rinse the anchovy fillets under cold running water to remove excess salt, pat them dry with paper towels, then add them to the blender (Photo 5).Add the mayonnaise (Photo 6).
Pour in one ladle of the reserved beef broth (Photo 7).Since the anchovies are already quite salty, wait until the end before adding any extra salt.Once all the ingredients are in the blender (Photo 8), blend until perfectly smooth and creamy (Photo 9).If necessary, add a little more broth to reach a silky consistency.
How to Serve
Unwrap the cooled beef (Photo 10), remove the kitchen twine and slice it very thinly with a sharp knife (Photo 11).Arrange the slices on a serving platter (Photo 12).
Spread the tuna sauce generously over the meat and serve immediately (Photo 13).