Step 1Rinse the meats except for the sausage under cold running water, then place them in a 10-quart stock pot with enough cold water to cover. Add the salt, potatoes, carrots and turnips. Bring to a simmer over low heat, frequently skimming off the foam, about 30 minutes.
Step 2As the broth begins to simmer, add the zucchini, parsley, celery and onion studded with the 4 cloves. Cook for another 30 minutes and then begin to check the doneness of the various vegetables and meats, removing them when they're done (usually beginning with the potatoes, zucchini and carrots followed by the chicken breasts, veal shanks and oxtail). The last is the tri-tip or brisket, which takes about 40 minutes to cook and should have a pink center when done. Turn off the heat and remove and discard the parsley, but leave the celery ribs and the onion to cool with the broth in the pot.
Step 3Bring a medium pot of water to a boil and add the sausage. Turn the heat to low and simmer for 40 minutes. When ready to serve, remove the casing and slice.
Step 4Serve the boiled meats and vegetables warm. They should be put back into the still-warm broth, then taken out shortly before serving and carved at the table. Arrange the carved meats and sausage according to type in the center of a warm serving platter and surround them with the sliced vegetables, also grouped according to type. Place the Dijon mustard, cornichons and mostarda di Cremona in bowls and the olive oil and vinegar in cruets and offer with salsa verde as condiments.