Put roast, broth, Italian seasoning, pepperoncini peppers and giardiniera in a crockpot and cook on low for 18 hours.
Turn meat over at the 6th and 12th hour intervals.
At the 17th hour, slice sweet green peppers lengthwise and cook in water on low heat until soft.
Pull roast apart with two forks to shred. Serve piled on your choice of bread, laying green peppers on top.