Caramelized Onion Quiche Recipe

Ingredients

• 2-3 large red onions (about one pound total), French-cut (see below)
• 1 recipe pie dough (see Pâte Brisée recipe)
• 2 tablespoons extra virgin olive oil
• Salt and freshly ground pepper
• 2 teaspoons balsamic vinegar
• 6 ounces Gruyère cheese, grated (1 1/2 cups)
• 3/4 cup milk
• 1/4 cup heavy cream
• 3 large eggs
• Pinch nutmeg