Place roast in slow cooker. In a bowl, add the beef broth with Cajun/Creole Seasoning and Brown Gravy Mix. Whisk together and pour over the roast.

Cook on LOW for 8 to hours or on HIGH for about 4 1/2 hours. Remove roast from slow cooker and shred.

In a small bowl, combine cornstarch with a little water. Whisk in cornstarch to thicken the cooking juices to make a gravy. Return meat to crockpot.

To assemble po-boys: Split french bread in half and toast. Place meat on half of bread. Spread mayonnaise on other half of bread. Top with shredded lettuce, tomato slices and pickles. Serves 8.