For Crock Pot:
Put the chuck roast in the crock pot.
Sprinkle Hidden Valley Ranch Dressing mix on the roast.
Sprinkle the au jus mix on top of that.
Drop in the pepperoncinis.
Drop in the butter.
Cook on low for 2 hours.

For Sous Vide:
Soften the butter, mush it up, and cover both sides of the roast.
Coat the roast with the dressing mix and au jus mix like you would do a dry rub.
Put the roast in a sous vide bag with the 5 pepperoncinis.
I did mine at 137° for about 51 hours.

In both cases, once the meat was done I set it aside and used whatever liquid it created, plus whatever water I needed, to cook up some potatoes, carrots, and onions.