Twice Baked Sweet Potatoes

Ingredients

2 tablespoons butter

3 small to medium yellow onions, sliced

Water, broth, balsamic vinegar, or wine (optional)

Coarse kosher salt and freshly ground black pepper

4 large sweet potatoes

3 ounces Gruyere cheese, shredded

Preheat the oven to 400ºF.

Heat butter in a large cast iron or stainless steel skillet over medium heat. Once melted, add the onions and stir to coat. Turn the heat down to medium low. Allow the onions to cook, just barely sizzling and stirring every 5 or 10 minutes, until very soft and golden brown, about 1 hour. If they start to dry out you can add a bit more butter. When the onions are dark enough you may want to deglaze the pan with a little water, broth, balsamic vinegar, or wine. Stir the liquid into the onions, allowing all the browned bits from the bottom of the pan to be picked up and absorbed into the mixture. Season with salt and pepper to taste.

While the onions are cooking, rinse the sweet potatoes and prick the skin with a fork a few times to allow steam to escape as they cook. Wrap each potato tightly in aluminum foil and place on a baking sheet in the preheated oven until soft and easily pierced with a fork, about an hour.

Preheat the broiler to high and set an oven rack in the highest position.

Allow the sweet potatoes to cool enough so you can handle them. Cut each potatoes in half and fluff up the inside carefully with a fork. Distribute caramelized onions amongst the potatoes, then top with shredded Gruyere.

Place sweet potato halves on a baking sheet and broil a few minutes, watching closely, until the cheese is melted and just beginning to brown.

Found Here