Srsly. So I know I've posted almost nothing but grilled cheese pictures lately, but I at least have some justification for this particular one.
The recipe for this grilled Gruyère and marinated onion sandwich is from the LA Times... who did a little recipe slide show to mark the occasion.
Anyway... great, great sandwich. Like the technique of toasting over low heat very much... I've always done it medium high, which tends to char the bread by the time you get the cheese all nice and gooey. A simple thing that can make a big difference: take your time. I prefer a more open crumb than the country bread they suggest, however, because you get that awesome semi-burnt cheese effect as the cheese oozes through the holes. The marinated onions are awesome... don't go light on them! Pile them on in a full layer. The marinating cuts the the sharpness of the raw onions by quite a bit, but the vinegar still gives them a little bite. Since a smallish onion will make a full cup of sliced onions I just doubled that part of the recipe and had plenty to pile on and plenty left over for a salad (or whatever). Also, whoever thought of putting mustard on a grilled cheese is a certified genius. I'm sorta sad that the first time I had it was only a couple of years ago (at Hi-Rise)... all those grilled cheese opportunities missed. Oh well.
Besides the time to marinate the onions, this couldn't be an easier recipe... and no special ingredients required.