Heat the oven to 325°F and season the top round roast with the salt and black pepper.
Heat the vegetable oil in a covered Dutch oven over medium-high heat and brown the roast for 4 minutes per broad side.
Pour in the broth and Worcestershire sauce, then stir in the oregano, garlic powder, onion powder and crushed red pepper around the beef.
Cover and roast for 70 to 90 minutes, turning once, until the center reaches 145°F.
Transfer the beef to a board, rest it for 15 minutes and chill it in the freezer for 30 minutes until firm but not frozen.
Slice the beef as thinly as possible across the grain, using a sharp slicing knife.
Skim excess fat from the jus, return the slices to the pot and warm them gently for 5 to 8 minutes until saturated and at least 165°F without boiling them tough.
Split the rolls without cutting through the hinge, fill each with hot sliced beef and spoon over 2 tablespoons jus.
Top each sandwich with 2 tablespoons giardiniera and serve with additional strained jus for dipping.
