1 tablespoon olive oil
1/4 pound pancetta, cut in a small dice
2 cups thinly sliced onion (about 3 small onions)
2 teaspoons chopped fresh rosemary
1/2 teaspoon salt
1/4 teaspoon pepper
1/4 teaspoon nutmeg
1 pound Yukon Gold potatoes, thinly sliced (about 2 medium)
1 pound yams, thinly sliced (about 2 medium)
1/2 pound Fontina Valle d’Aosta, grated
1 cup chicken broth, heated

Preheat oven to 375° F. Heat oil over medium in a 9-inch cast iron skillet or Dutch oven with a fitted lid. Cook pancetta in the oil until it begins to crisp and turn brown, 4 to 5 minutes. Add onions, rosemary, salt, pepper, and nutmeg. Cook, stirring frequently, until onions are a deep golden color, 8 to 10 minutes. Remove pancetta and onions from skillet and set aside.