1 tablespoon butter

1 tablespoon olive oil

3 1/2 cups chopped onion

1/4 teaspoon kosher salt

2 ounces Gruyere cheese, shredded and divided

2 tablespoons chopped fresh chives, divided

1/3 cup mayonnaise

1/3 cup sour cream

1/4 teaspoon kosher salt

1/4 teaspoon freshly ground black pepper

6 bacon slices, cooked and crumbled

 

Preheat oven to 425 degrees F. Heat butter and olive oil in a large cast-iron skillet over medium heat.  Add onions and salt to the pan and sauté© 5 min, stirring frequently.  Reduce heat to medium-low and cook, stirring occasionally, for 30 minutes or until the onions are a deep golden brown.  Cool slightly. Reserve 2 tablespoons cheese.  Combine cheese, caramelized onions, 1 tablespoon chives, and the remaining ingredients in a medium bowl.  Taste and adjust seasonings if necessary.  Transfer the mixture to a 1 quart glass or ceramic baking dish (I used and 8-inch cast-iron skillet) coated lightly with cooking spray.  Sprinkle with reserved 2 tablespoons cheese.  Bake at 425 degrees for 20 minutes or until golden brown and bubbly.  Sprinkle with remaining 1 tablespoon chives.