French Grilled Cheese Sandwiches with Marinated Onions

by Laura Donnelly — April 4, 2007

Our third sandwich of the week is a modern version of a good old-fashioned grilled cheese. If you prefer sharp cheddar cheese or Taleggio or Fontina, feel free to use these instead. In summertime, make sure you add a big slice of beefsteak tomato and leave out the mustard.

Makes 4

1/3 cup olive oil
3 Tablespoons white wine vinegar
1 Tablespoon salt
2 teaspoons black pepper
1 large Vidalia or other mild onion, sliced
8 slices whole wheat or sourdough bread
1/4 cup whole-grain mustard
8 ounces Gruyère cheese, thinly sliced

1.  Combine oil, vinegar, salt and pepper, and onions.  Let marinate for about 1/2 hour.  Drain.

2.  To assemble sandwiches, butter or oil outside of bread slices.  Lay half of cheese on unbuttered side of half the bread.  Scatter some onions over cheese, then cover with rest of cheese.  Spread mustard on inside of other bread slices, then grill or pan sauté until golden brown and cheese is melted.