re: Cut of Beef for Roast Beef Sandwiches?

An eye of round is ok but I prefer the top round or a steamship round which is both and what you would see at say a wedding or a brunch buffet. It has the rump cut off.

Roast on a rack to just medium rare then let cool. Use the drippings to start your au jus and add beef stock or beef base and a bit of water to finish the jus. Bring it to a boil and scrape the fond off the bottom and let it reduce until you like it. Whisk just a small bit of butter for a sheen and richness while still keeping it loose as a jus should be.

For flavor I like salt, pepper, bit of whole garlic and fresh thyme.

When ready slice the cooled roast very thin ( because if not it is tough) and drop into the au jus to just warm through. Put on a toasted roll and serve au jus on side. I like lettuce and tomatos on them.

Do the same as above with a pork loin and make pork french dip. Lamb as well.