→ Mushroom Filling
01 -
2 tablespoons unsalted butter
02 -
1 tablespoon olive oil
03 -
1 shallot, finely chopped
04 -
2 cups sliced mushrooms (Portobello, Cremini, or Shiitake)
05 -
1 teaspoon thyme, fresh or dried
06 -
1 tablespoon balsamic vinegar (optional)
07 -
Salt and freshly ground black pepper, to taste
→ Sandwich Assembly
08 -
4 slices Swiss cheese, or Gruyère
09 -
8 slices bread (Rye, Sourdough, or Artisan)
10 -
Butter, as needed for bread