The thing about using a waffle iron here is that by some miracle of physics it turns out a grilled cheese that has even more crispy, buttery surface area than you get with a flat skillet. You’ll easily want another one of these in the same sitting, so feel free to double the recipe and just make one sandwich in the waffle iron at a time. You could also make this in an electric skillet (four at a time!) or the old-school way: Wrap your sandwich in nonstick foil and hit it for about two minutes on each side with a clothing iron, set on the highest heat level, without steam. Crazy but true!
Variations
GOUDA AND APPLE: Spread some honey mustard on the unbuttered sides of the bread and add a couple of very thin slices of tart apple, such as Granny Smith,
along with 2 ounces of sliced Gouda. Proceed as above.
HAM, GRUYÈRE, AND CRISPY ONIONS: Spread Dijon mustard on the unbuttered sides of the bread. Arrange a thin slice of ham, a slice of Gruyère, and a sprinkling of store-bought crispy fried onions on top of the mustard, then add a second layer of Gruyère and ham. (The onions stay crispy this way.) Proceed as above.
SALAMI, PROVOLONE, AND PEPPERS: Instead of butter, brush the bread with extra-virgin olive oil. Put a slice or two of salami (Genoa, pepperoni, or soppressata), provolone, and a couple of chopped pickled hot peppers (such as peperoncini or cherry peppers) in the middle and proceed as above.