To a small pot on the stove add the water and packet of au jus gravy mix whisk well and bring up to a simmer, let simmer for 3 minutes stirring occasionally.
Stir in the roast beef and let cook for 3 minutes.
Remove the roast beef with a slotted spoon and set to the side. Save the au jus gravy for dipping the sandwiches in.
Turn oven to broil. Open the hoagie rolls and place them open on a sheet pan place the slices of provolone on the rolls and broil for 2 minites or until the cheese is melty.
Fill the hoagie rolls with the roast beef and serve with the au jus for dipping