Preparation:
wash the tripe carefully and boil in abundant water for at least two hours along with all the other vegetables (celery, carrot, onion, parsley, garlic, a slice of lemon and a splash of vinegar). When it is cooked, drain it, scraping well with a knife to remove the fat. Forcefully rub both sides with half an onion and then with two lemons. Rinse thoroughly under running water, dry, then cut into thin strips. Season with salt, pepper, and spices and leave to gain flavour until the following day.
Chop the celery, carrot, and onion and sauté in the butter; add the tripe and a cup of stock containing a little tomato sauce. Leave to cook slowly for about three hours, adding the rest of the stock a little at a time.
Serve sprinkled with freshly grated Parmesan. At this point, if possible let the tripe rest for up to a whole day. Then put back on the heat for about an hour.
Serve hot.