How To Transform Leftover Prime Rib Into Flavorful French Dip Sandwiches

If you've ever prepared a prime rib roast at home, you know that it's no small cut of meat. A full roast encompasses around 7 large beef ribs, enough meat to serve a dozen or more guests — but it's worth getting a big cut so you can have some leftovers to feast on. As long as you have the oven on, planning for some extra roast beef to transform into a tasty French dip sandwich the next day is a winning idea, especially when you realize the au jus sauce classically served with prime rib makes the perfect juicy dip for your sandwich.

Although French dip can be made from many cuts of beef — even shredded oxtail or pot roast — the classic version features thinly sliced beef, toasted French bread, melty cheese, sautéed onions and mushrooms, and of course that delicious beef broth for dipping. A cold bit of leftover prime rib is just the right bit of beef to make a tender sandwich.

The best French dip sandwiches are stuffed with tender meat that's easy to bite into, and prime rib is a notably tender cut of meat. It's easiest to slice a roast when it's still chilled, so get out your best slicing knife and cut your roast against the grain while it's fresh out of the refrigerator. The slices of beef will warm up quickly with a brief dunk in barely simmering au jus sauce.

To get the rest of the sandwich prep ready, slice up half an onion and a handful of button mushrooms, and sauté them in a little butter until they're slightly browned and fragrant. Meanwhile, grill or toast split French rolls, layer them with your favorite cheese. When the rolls are ready you just need to pile the warm, sliced prime rib onto the prepared rolls, adding mushrooms and onions to taste, and be ready to bite into the best beef sandwich you've ever made, thanks to that leftover prime rib roast.