Trim excess fat from the rump roast, and place in a slow cooker. Add the beef broth, onion soup and beer. Cook on Low setting for 7 hours.

When meat is done, remove from juice and slice thin. (It will probably just fall apart which is fine, I just put meat crumbles in my crescent rolls.)

Preheat oven to 375

Spread out your crescent rolls and add a small amount of meat and shredded mozzarella to each one.

Fold the corners in over the meat to hold everything in and then roll up.

Bake for 13-15 minutes until golden brown.

Serve with juice from slow cooker.