Baked Sweet Potatoes with Caramelized Onions and Shaved Parmesan

• 6 medium sweet potatoes (8 ounces each)
• 1 tablespoon unsalted butter
• 4 large yellow onions, cut in half, then into 1/2-inch-thick half-moons
• 3 tablespoons sugar
• 1 teaspoon coarse salt
• 1/4 teaspoon freshly ground pepper
• 2 tablespoons balsamic vinegar
• 1 1/2 ounces freshly shaved Parmesan cheese (about 1/2 cup)

1. Preheat the oven to 450F.
2. Place the potatoes on a baking sheet; bake until tender, about 45 minutes.
3. Meanwhile, melt the butter in a large nonstick skillet over medium-low heat.
4. Add the onions; cook until soft, about 15 minutes.
5. Sprinkle with the sugar, salt, and pepper; toss to coat.
6. Continue to cook, stirring occasionally, until the onions are very soft and caramelized, about 1 hour more, adding water 1 tablespoon at a time if the pan dries.
7. Stir in the vinegar.
8. Set aside; keep warm.
9. When the potatoes are tender, split them open, and top with the caramelized onions and shaved Parmesan.
10. Serve warm.

sweet potatoes, unsalted butter, yellow onions, sugar, coarse salt, freshly ground pepper, balsamic vinegar, freshly shaved parmesan cheese

Taken from www.epicurious.com/recipes/food/views/baked-sweet-potatoes-with-caramelized-onions-and-shaved-parmesan-392871 (may not work)