Best Prime Rib Sandwich

"This Best Prime Rib Sandwich is mouth-wateringly good and is packed not only with prime rib but caramelized onions, provolone cheese, garlic butter, and mayo! You will save prime rib just for this sandwich!! Or heck, go and grab some from the deli to make this!! I know you want to reach in and grab this leftover prime rib sandwich for that epic bite. Quickly invite the family over for a Sunday dinner so you can enjoy this on Monday!"