Hat tip ;)
The best roast beef sandwich comes from Brennan & Carr in Brooklyn. Roll & Roaster is a close second. I understand Boog Powell of Oriole fame has a roast beef concession that makes a pretty good sandwich.
Sorry, Mayo on roast beef is like ketchup on ice cream. A roast beef sandwich should be on a roll with au jus. That’s it.
https://www.brennanandcarrbrooklyn.com/
It’s a good read.