The Food Lab: Better Home Cooking Through Science

the meltiness of American. A good compromise is to use
one slice of American for the goo factor and an extra slice
of a more flavorful sharp cheddar or Swiss (or, if you want
to be really fancy, Gruyère).
Finally, if you want to go full cheese on this one, I like to
add a layer of Microplaned Parmigiano-Reggiano to the
exterior of my sandwich. It crisps up like an Italian frico in
the skillet, giving you an extra layer of cheesy crunch.