Yield: 6 to 8 servings.
1 Tbsp. olive oil
1/4 lb. pancetta, cut in small dice
2 cups thinly sliced onion (about 3 small onions)
2 tsp. chopped fresh rosemary
1/2 tsp. salt
1/4 tsp. pepper
1/4 tsp. nutmeg
1 lb. Yukon Gold potatoes, thinly sliced (about 2 medium)
1 lb. yams, thinly sliced (about 2 medium)
1/2 lb. Fontina Valle d'Aosta, grated
1 cup chicken broth, heated
Preheat oven to 375°F. Heat oil over medium heat in a 9" 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.
In the same skillet, start layering 1/3 of the potatoes, followed by 1/2 of the onion mixture and 1/2 of the Fontina Valle d'Aosta. Repeat the same layers and finish with the last 1/3 of the potatoes. Pour chicken broth over all.
Cover skillet and bake 40 minutes. Uncover and bake another 20 minutes or until potatoes are soft. Cut into wedges and serve directly from the pan.