Start by heating the au jus in a saucepan over low to medium heat until hot.
If you are slicing the roast beef yourself, you can use a sharp knife, a mandolin, or a meat slicer. I prefer the roast beef to be thickly sliced for this sandwich.
The sliced beef should be warm before serving. However, if it is cold, then you will want to add some slices to the hot au jus to heat it up until warm.
Dip the bottom part of the French roll into the hot au jus
Next, drop the top sliced part of the French into the au jus.
Stack several slices of the hot beef onto the sandwich. At this point, you can also add on your condiments, sauce, or cheeses.
Slice the sandwich and serve with assorted toppings, cheeses, sauces, and hot au jus.
Notes
Make-Ahead: If all the ingredients are kept separate, you can prepare this French Dip sandwich recipe up to 3 days ahead of time.How to Store: Store the toppings, bread, and buns separately covered in plastic wrap for up to 1 week in the refrigerator. These ingredients, unfortunately, will not freeze well.How to Reheat: Add 1 to 2 cups of the au jus to a saucepan over low to medium heat. Place in the desired amount of sliced beef and heat until warm. Serve following the sandwich-making procedures.