Ah Po would use these soy sauce-enriched drippings to make a sauce, a very thin one, similar to au jus, which later on, I would transform into a thick and delicious gravy in my own kitchen.

But of course, no prime rib is complete without au jus, its traditional sauce pairing. Adding au jus to a prime rib dinner ...

Randolph cut up the leftover tri-tip roast into thin slices. He made an au jus sauce. The sauce is simple. You just combine a can of French onion soup with a can of beef broth soup in a sauce pan.