French Dip Sandwiches

I love french dip sandwiches, and I like them fast and easy.  Before this whole diet change, it was one of those meals that I could throw on the table in under 15 minutes, and not even think about it.  Well, we haven't had French Dips since then, because I just didn't feel like it.  Well, the other day I actually did feel like it, and realized that we could no longer use the packets for the Au Jus sauce (yes, I am that lazy, or at least I used to be that lazy).  And, I wasn't cooking a roast, so no drippings there....So, I decided I needed an easy throw together Au Jus recipe, so I could still have my easy throw together French Dip sandwiches. 

French Dip Sandwiches and Au Jus

1 lb thinly sliced roast beef
4 gluten-free buns (I actually had some homemade hot dog buns in the freezer that I used and they were perfect, they held up really well being dipped in the Au Jus)
Au Jus for dipping

Au Jus
1 1/2 cups beef stock (I used Swanson beef stock)
1 teaspoon Worcestershire Sauce (I use Lea and Perrins because it's gluten and soy free)
1/4 teaspoon garlic powder

Instructions
Mix ingredients and bring to a boil.  Serve warm with assembled sandwiches.