For the marinade: Bring the vinegar, garlic, sugar, salt, oregano, fennel seed, black pepper, and 2 cups water to a boil in a medium saucepan. Boil for 5 minutes. Let cool. Place the brisket in a large baking dish and cover with the marinade. Let rest, covered, overnight in the refrigerator.
Preheat the oven to 325 degrees F.
For the brisket: Smear with the tomato paste and place in a clean large baking dish. Cook, covered, for 5 hours. The meat should easily come apart. Cool.
Slice the brisket against the grain in 1/8-inch thick slices. Reserve the jus separately. Keep the brisket slices warm in the jus.
Remove the insides of the rolls and smear with horseradish mayonnaise, to taste. Put 2 slices cheese, 2 to 3 roasted tomatoes, and a handful of pepperoncini on each roll. Place in the oven to crisp the rolls and melt the cheese. Meanwhile, cook the eggs to over-easy. Place 2 eggs on each roll. Top with about 4 ounces brisket and drizzle with some jus. Wrap and slice in half. Buen gustaio!
Preheat the oven to 275 degrees F. Combine all the ingredients and roast for 1 hour.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.