For this recipe you will need English muffin or egg rings. If you do not have either of these, you can cut the bottom and top off of tuna cans and wash them thoroughly or use round, metal cookie or biscuit cutters. They'll all get the job done.
If, in some alternate universe, you should happen to have leftovers of these they should keep well wrapped in plastic at room temperature for a day or so. You could conceivably store these in the freezer, but that's uncharted territory for me. There are never leftovers. Ever.