Leftover roast beef or prime rib, shaved thin
Saute the onions until cooked through. split the roll open and layer shaved beef then onions and top with swiss cheese. Bake until warmed through and cheese is melted. This came out really good. You could add horseradish sauce and also mushrooms if you like those things. It was a great way to use up leftover roast beef from Christmas dinner. We will make this one again in the future.