2 small black truffles
1 small wedge Swiss Gruyere
1/2 small yellow onion, caramelized
bread or ciabatta
knob of truffle butter
Start by caramelizing the onions. To do so, cut them into thin slivers and toss them until lightly coated with oil. Toss them into a pan and cook them on medium high heat for ten minutes or so, stirring as they wilt. Then, turn the heat down a bit and add a pinch of salt. Cook the onions on low to medium heat for twenty minutes or more, stirring occasionally. The onions will sometimes stick to the pan -- that's fine, let them brown. In fact, I let mine go a little long so that they crisped up a bit. It's not perfect caramelizing, per se, but it adds some nice texture to the sandwich. After cooking for a total of around half an hour, you should have some tasty caramelized onions. Put them aside for now.
Then, grate your gruyere and cut up your truffle.
Once everything's ready, cut your ciabatta in half and butter the insides. . Put the bread down into a pan, top with cheese, truffles, onions, and more cheese. Place the other piece of bread on top, and cook on low heat. Once the cheese has melted and the bread has browned