In a large skillet heat the oil over medium hot heat. While the oil is heating up, sprinkle the beef with the salt and pepper. Once hot, add the pieces of beef and sear each side for about 45 seconds.
Place the meat in the slow cooker. Don’t add the excess oil, just the meat.
Add the garlic, onions, pepperoncini peppers, and sweet cherry peppers (or giardiniera) into the crockpot.
In a large liquid measuring cup or a mixing bowl, dissolve the bouillon in the beef broth. Add the dressing mix, Italian seasoning, red pepper flakes, and pepperoncini liquid.
Pour the liquid mixture over the beef and onions/peppers in the crockpot.
Cover and heat on low for 8-10 hours or high for about 6 hours.
Remove the meat from the crockpot and shred.
Pour all the liquid out of the slow cooker through a strainer. Return the peppers back into the pot with 2 cups of the liquid. Return the meat to the slow cooker and toss gently to combine. Cook an additional 20-30 minutes.
To serve, open the hoagies and toast on a baking sheet for about 4-6 minutes at 375 degrees F.
Generously add beef to one side of the toasted hoagie and top with provolone cheese. Return to the oven for about 1-2 minutes until the cheese is melted. Remove from oven and top with additional peppers.
Dip in extra juice from the slow cooker, if desired.