There are a few differences between Gratin and Scalloped Potatoes. The first notable difference is how each recipe uses - or doesn’t use - cheese. Gratin potatoes contain a top layer of cheese that is baked until golden brown towards the end of the baking process, while scalloped potatoes typically contain no cheese at all.  The other key difference between these two recipes is the use of bread crumbs. Some traditional gratin recipes will mix bread crumbs with the cheese for a little extra crunchy bite. Scallop potatoes contain no bread crumbs, just lots of milk, flour, and butter.