[quote]Aside from having to be sliced, the only other rule here is that your bread can't be too perforated with air bubbles (or your cheese will drip out) or sliced too thick (lest your cheese not melt). White bread and American cheese is what many of us grew up on, but if you want to go fancier, feel free to use a nice hand-sliced Italian ciabatta, a good sourdough, or a French boule. Grilled cheese is also a great way to use up day-old bread, since the grilling process will resuscitate it a bit. A grilled cheese doesn't work with just any old cheese. You've got to have a cheese with just the right melting characteristics. Dry, crumbly, fresh cheeses like goat cheese won't melt properly. Ditto for overly aged cheeses like a Parmesan or hard Pecorino. Some of our favorites include the classic American and young Cheddar, Swiss-style cheeses like Gruyère (or its French cousin Comté), or young Italian and French cheeses like Taleggio or Brie. As long as it melts, it's got a place in our sandwiches. If you do like the flavor of a non-melter, it's acceptable to treat it like another topping—that is, pair it with a cheese that does melt. A mozzarella and feta combo makes a fine sandwich, as does Fontina and Parmigiano, for instance.[/quote] http://www.seriouseats.com/2015/02/best-grilled-cheese-sandwich-recipe-variations.html Instructions unclear, microwave covered in cheese.