I found this recipe by Julie on Better Than Burgers. I love French Dip. This was really simple to make and it was good. Not my favorite, but I think part was the roast beef. I don't think it was as good as I usually get at Publix. I actually made this over a week ago. Just never got around to posting!
Easy French Dip Sandwiches
3 lb. sliced deli roast beef
1-2 packages of Aujus mix (i.e., McCormick's Mix)
6 slices of Swiss or Provolone Cheese
6 sliced sandwich rolls (French Rolls, Kaiser Rolls etc...anything you would like)
In a large frying pan place meat with 1 c. water, simmer/steam until warm. Prepare Aujus mix according to package directions. Butter inside of roll (both top and bottom) and place butter side down in hot frying pan. Cook until browned. Place 1 slice of cheese on inside of browned bun. Top with 1/2 lb. of warmed roast beef (I patted mine dry with a paper towel before putting it on the bun). Pour Aujus in a small bowl and eat to your hearts content.