This is the BEST recipe.
3-4 lb. Beef Round Steak (or any type of beef roast)(chuck roasts you can shred when cooked or I prefer the rolled or rump roast and slice when done)
1 packet Onion Soup Mix
1 packet Au Jus Seasoning
1 (15 oz) can of Beef Broth or Stock
½ cup water
4 slices mozzarella cheese
Sub rolls (I like Bolillo Rolls)
Put beef roast in slow cooker. In a medium bowl, combine Beef broth, Onion soup mix, Au Jus seasoning and water and stir until combined. Pour mixture over beef, put cover on slow cooker and cook on low for
about 8 hours. An hour before serving, shred meat with two forks or take it out and slice thinly. Place meat back in the slow cooker for another hour.
When ready to serve, place several slices of beef on roll, add sliced mozzarella cheese and place under the broiler (or use broil option on toaster oven). Watch carefully, broil for just a couple of minutes until cheese is melted and roll is just slightly toasted.
Serve sandwich with a bit of Au Jus from the slow cooker (you may want to strain it first). Also, I added just a bit more beef broth to our Au Jus.
Cook's Note: Optional toppings include sauteed onions, green peppers and mushrooms.
Also, instead of the water, you can substitute with more beef stock if you like.