What's your special ingredient/technique that makes your grilled cheese a little bit better than the rest?

Grilled cheese… aaah. A sandwich so simple in design yet deliciously complex in taste. Everyone makes it there own special way, so I want to know, what does everyone do to their grilled cheese that makes it a little bit better? I do two things. I slow cook the sandwich. I know some people cook on high heat for a crisper toast like bread. I cook slow, so it’s more of a french toast type of texture, soft & gooey. I also grind fresh black peppercorns on the outside (buttered side) of the bread slices.

So what do you do? I’d love to try some new variations on this simple recipe. It’s such an easy dish to play with & I’d love to know how other people make it.