When you put bacon in a pan, you don’t need to grease it – not really. This was demonstrated for me in Croatia — there was a guy selling freshly caught fried sardines, served with a piece of bread (i can not overstate their excellence), and he explained to me that you just get the iron hot enough before you put the fish on it, and they will cook in their own oil while sufficiently lubricating the cooking surface.
And so it is with bacon. And bacon has so much grease that once you take the bacon out (I suggest taking it out while it’s still chewy), the pan is full of grease. You can do various things with this — basically anything. I will use this grease to cook my eggs, and maybe even make a bacon grease grilled sandwich. Sometimes the pan is still slick after that, so I just leave it for the next day’s eggs. That’s right: leave it. Preserve that grease — don’t throw it out! Bacon grease is precious, precious, precious.
But perhaps we should pause a moment, and consider the grilled-cheese sandwich. We all know that a grilled cheese sandwich is better with tomatoes — but some people put the tomato in with the cheese. This is fine, I suppose, but it is certainly not the optimal use of a tomato in this context. Unless the tomato slice was considerably cooled before being nestled between the bread, it’s going to be a hot tomato, and this is certainly not ideal
One of the best things about tomatoes on sandwiches is that the tomato is cold. That’s right – the key to an excellent sandwich is contrast. The tomato provides a moisture contrast with the bread, and it can provide a temperature contrast (I like to call it a coolness contrast) with the hot cheese and bread. There are all kinds of contrasts to be achieved on a sandwich… we can’t get into all of them now, but you should know that a cold tomato is better than a hot one.
Therfore: add the fresh tomato slice after the sandwich has been grilled, and on top of the bread. An open-faced bacon grease closed grilled cheese sandwich. It will not disappoint.