Slice rolls open and lightly toast under the broiler.
Pile a generous amount of roast beef on the bottom half of each roll. Cover with roll top.
Serve sandwiches immediately along side small bowls of the warm au jus or dipping sauce of your choice.
Notes
If you want to add cheese place it on top of the beef and quickly melt under the broiler.If you don't have pan drippings from cooking the beef from scratch, you can create a flavorful au jus by simmering high-quality beef broth with similar aromatics.