Slow Cooker Meatball and Gravy Sandwiches Well, I love the idea of this slow cooker recipe. I've actually, made something similar to this - and really like the last poster - who used Mushroom Gravy. I made my meatballs fresh - and find the premade ones too salty. This photo HOWEVER, really disturbed me. It looked like a cooked version of the baby Alien Creature in the Movie Aliens. The photo really turned me off.