Start by sautéing some pancetta, but into lardons or cubes, in olive oil in a large pot or pressure cooker. (The traditional vessel for cooking tripe is a large terracotta pot, and using one does seem to give you extra depth of flavor.) Add a battuto of onion, carrot and celery, and continue sautéing, seasoning with salt and pepper, until the vegetables are nice and soft. (Adding a tablespoon of water from time to time ensures that the soffritto will not brown.) Add a peperoncino (or red pepper flakes) and then your pre-cooked tripe (see below), cut into bite-sized pieces. (Typically, the tripe will be cut into strips.)
Mix it all well, and allow to simmer so that the tripe begins to insaporire, or absorb the flavors of the soffritto. Add a splash of white wine, and when it has evaporated, add crushed tomatoes. The more you add, the more saucy the dish will be. (Any excess sauce is absolutely wonderful over pasta!) Cover and simmer until the tripe is tender but still ever so slightly chewy. In a pressure cooker—which comes in very handy for this dish—the trip will need about an hour of cooking. In a regular pot, it will take about 3 hours. The exact cooking time will vary, depending on how well pre-cooked the tripe is.
About 5 minutes before you are ready to serve the tripe, add a handful of mint. (In Rome, they use a lovely local mint called mentuccia but, alas, as far as I know, it is unavailable elsewhere.) Serve topped with a generous grating of pecorino cheese.
NOTES: In Italy, you can find tripe that has been almost entirely pre-cooked, so that you need only simmer it with the tomato sauce for, say, 30-45 minutes and it’s ready to eat. Outside Italy, you can sometimes find pre-cooked tripe in Italian neighborhoods. Otherwise, tripe does usually come partially pre-cooked, but needs further cooking before you can use it for this dish. Pre-cooking also removes some of the ‘gamy’ flavor that tripe can sometimes have. To pre-cook tripe, simmer the whole trip in water to cover with an onion, garlic and a spring of parsley (you can add carrot and celery, too, if you like) for about an hour.