Beef tripe comes from the muscular wall of the cow's stomach. It is not the same as cow intestines. There are three kinds of beef tripe sold for cooking. Honeycomb tripe or blanket tripe is what you need for this recipe. Book tripe is not recommended.It takes about six hours of simmering to tenderize beef tripe on the stovetop. It takes eight to ten hours in a slow cooker depending on the setting you choose. In a pressure cooker, it takes a little over two hours.How you want to tenderize the tripe is up to you. But I highly recommend that you add plenty of salt to the cooking liquid. And to neutralize any strong smell, a stalk of lemongrass and a few slices of ginger will help tremendously.