Bring a pot of water to a boil and add 1 carrot, 1 red onion, and 1 celery stalk. Once the water reaches a rolling boil, add the veal snout and let it cook for about 2 hours.
Meanwhile, finely chop 1 carrot, 1 red onion, 1 celery stalk, the garlic, parsley, and sage. Sauté the mixture in a saucepan with the olive oil for about 10 minutes.
Next, add the meat from the veal snout, cut into cubes, and brown for another 5 minutes. After that, deglaze with the red wine.
Once the alcohol has evaporated, add the tomato purée to the pan and season with salt and ground chili pepper. Let everything simmer for about 1 hour, or until the meat is tender, adding hot vegetable stock whenever the mixture becomes too dry.