Place the roast into the crock of a slow cooker. Pour the entire jar (peppers and juice) of pepperoncini peppers over the roast. Add the stick of butter, then pour the dry ranch dressing and dry Au Jus over the top. Cover with the lid.
Cook on low for 8 to 10 hours (or high for 4 to 5 hours).
Once finished, shred with a fork and serve.
You can serve with the pepperoncini or without, depending on your taste.