Add the roast to the bottom of the slow cooker and sprinkle with the salt, pepper, garlic powder, oregano, basil, paprika, and red pepper flakes.
4-6 pounds boneless beef chuck roast, 2 teaspoons Kosher salt, 1 teaspoon freshly ground black pepper, 2 teaspoons garlic powder, 2 teaspoons oregano, 1 teaspoon basil, 1 teaspoon paprika, 1/2 teaspoon red pepper flakes
Cover with the sliced onions and half of the jar of sliced pepperoncini peppers, then add the reserved pepperoncini juice, beef broth, and Worcestershire sauce.
1 yellow onion, 16 ounces sliced pepperoncini peppers, 1/3 cup of the pepperoncini juice, 14.5 ounces beef broth, 2 Tablespoons Worcestershire sauce
Cover and cook on LOW for 8-10 hours or on HIGH for 5-6 hours.
Preheat oven to 400°F. Butter and toast the rolls in the oven or in a skillet.
8-10 sandwich rolls or hoagie buns
Shred the meat using two forks. It should easily fall apart.
Use tongs or a slotted spoon to transfer the meat from the juices and place it on one side of each roll. Top with the remaining pepperoncini peppers, if desired, and giardiniera. Cover with slices of provolone cheese, then place in the oven just until the cheese is melted. Serve immediately.
16-20 slices provolone cheese, 1 jar Giardiniera