Preheat oven to 400 degrees. Season the roast with salt, pepper, and garlic powder and add to a large pan. Add 32 ounces of beef broth to the pot, to cover 3/4 of the roast.
Cook the roast to 140 degrees, or rare to medium rare.
Remove roast from the pan, cover lightly, and allow to rest for one hour. Meanwhile, strain the broth from the pan and reserve.
Use a sharp knife to slice the rested roast beef as thinly as possible. Add the slices of beef to a large bowl.
Add 48 ounces of pickled sweet cherry peppers, including juices, to the bowl with the beef. Add reserved beef broth as needed to cover the meat completely. Cover the bowl and let sit for at least six hours.
Add the contents of the bowl to a pot and simmer over medium heat for 20 minutes.
Cut the bell peppers into strips and toss in olive oil, salt, and pepper. Sautee or grill over medium-high heat until soft.
Assemble sandwiches by cutting open sandwich rolls lengthwise, leaving the back edge intact. Layer beef and bell peppers. Use tongs to dip the entire sandwich in the hot broth left in the pan after heating the meat. Add giardiniera to the sandwich and dig in!