This recipe is so good. We used to eat these all the time when we can purchase relatively inexpensive oysters nearby in the 1970's from the California coast but now I have to reserve this for special occasions. The recipe comes from the Plaza Hotel New York City. Life is sweet when I can have these while sipping great tasting white wine and seeing the bright reddish orange sun slowly going down the Pacific Ocean. Although these are great with oysters in half shelf, it also works fine with oysters already shucked and placed on gratin plate with the topping and baked. The presentation is better with half shelf, but gratin dish method works fine and maybe easier. If Using gratin dish method, discard the shells.