crockpot french dip sandwiches with gravy dip

I love love love McAllister's Deli's french dip sandwiches because they serve it with "comeback" gravy. And I do. Come back that is.  But eating out gets expensive, so I found a recipe and tweaked it a tad.  I have to say, it was pretty amazing.  And, it's a crockpot meal so it has the added bonus of being  quick and easy.  It makes about 4 sandwiches.

1 1/2 lbs of boneless round steak
1 envelope of onion soup mix (we couldn't find any without msg, but I am on the hunt.)
12 ounces of beef stock (KITCHEN BASICS brand!)
8 ounces of shredded cheese - I used mozzarella but you can use any kind you like
1 loaf of bakery French bread

Combine the beef stock and the onion soup mix in the crock pot and then add the meat.  Cook it on low for 8 hours.  Remove the meat and gently pull it apart with a fork. DO NOT THROW AWAY THE JUICE IN THE CROCK POT! You need that for the gravy.  Cut the French bread into four sections and then open them up.  Layer meat and top with cheese.  Wrap them individually in foil and pop them in a 375 degree oven for 15 minutes.  While the cheese on the sandwiches is melting, dump the juice into a sauce pan and bring it to a boil.  In a small cup mix about 2 tbs of corn starch with enough water to make it liquid. Add it to the boiling pot and reduce the heat to a simmer.  Whisk it while it simmers until it thickens. If two tbs of corn starch isn't enough, mix up some more and add. Just be a little careful; the gravy can get too thick.  Season the gravy to taste.

I served this with sliced cucumbers and hummus and potato chips (not terribly healthy, I know, but I LOVE to dip the potato chips in the gravy!)