INGREDIENTS
•
For Marinated Onions:
•
2 medium yellow onions, thinly sliced
•
1/3 cup extra virgin olive oil
•
2 tablespoons champagne vinegar
•
2 tablespoons kosher salt
•
I tablespoon freshly cracked black pepper
•
1/4 teaspoon lemon juice
•
1 tablespoon finely chopped chives
•
For Sandwiches:
•
4 tablespoons (1/2 stick) unsalted butter, room temperature
•
1/4 cup whole grain mustard
•
8 slices fresh sourdough bread
•
8 to 12 ounces Gruyere cheese, sliced 1/16 inch thick