Step 1Rinse the tripe, place it in a large saucepan and cover it with water. Add 1 tablespoon of salt and bring to a boil. Immediately remove the tripe from the water and rinse it under cold water. Remove any large chunks of fat.
Step 2Return the tripe to the saucepan, cover generously with more cold water, add 1 teaspoon of salt, the onion, carrot, celery, leek, bay leaves, thyme and black peppercorns. Bring to a simmer and cook very slowly until tender, about 3 1/2 hours. Cover and refrigerate in the cooking broth until cool.
Step 3Drain the tripe and cut it into 4-inch triangles. Combine the wine and the mustard and coat both sides of each piece of tripe with the mixture. Cover tightly and refrigerate overnight.
Step 4Before serving, remove the tripe from the marinade and remove any excess marinade.
Step 5Beat the eggs with 2 tablespoons of water and a dash of salt. Mound the bread crumbs in a shallow container.
Step 6Dip each triangle in the egg mixture and then in the bread crumbs, pressing both sides to make sure the tripe is heavily coated with a firm breading. Set aside.
Step 7Heat 2 to 3 tablespoons of oil in a large skillet over medium-high heat until quite hot. Add the tripe and cook about 4 to 5 minutes a side until well-browned. Drain on paper towels. This may need to be done in 2 or 3 batches. Add more oil as needed.