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Sweet Potato Gratin

Sweet potato gratin warms our souls! It is rich and filling, like any self-respecting potato gratin should be. Thinly sliced sweet potatoes are baked to perfection with a touch of garlic and rosemary, and a healthy dose of freshly-grated Gruyere and Parmesan. Savory, subtly sweet, and creamy, this dish is a decadent addition to any holiday table or festive fall meal.

  • Servings 6-8 people
  • Dish Side
  • Time 1.5 hours
  • Skill Beginner



1 Tbsp butter
3 lbs (1.3 kg) sweet potatoes
3 oz (1 cup) Gruyère cheese, finely grated
2 oz (⅔ cup) Parmigiano-Reggiano cheese, finely grated
4-5 cloves garlic, finely chopped
2½ cups heavy cream or half & half
2 sprigs fresh rosemary, finely chopped (about 1 Tbsp)
1½ tsps kosher salt
½ tsp freshly ground black pepper
¼ teaspoon freshly grated nutmeg





Preheat the oven to 400°F. Grease a 12” cast iron or deep oven-proof skillet with the butter.


Peel the sweet potatoes, then slice them into ⅛” thin rounds using a mandoline or sharp knife.


In a large bowl, combine half of the grated cheese (about ¾ cup), garlic, rosemary, salt, pepper, and nutmeg. Add the sliced potatoes and toss.


Working from the outside towards the center, stack the sliced potatoes into the greased skilled like a deck of cards on top of each other. Repeat this process until the potatoes form concentric circles in the skillet, and until all of the potatoes have been placed inside. The potatoes do not need to match up, as the different shapes and sizes will create nice variations in texture when the gratin bakes.


Pour the cream over the potatoes. Cover the skillet with aluminum foil and bake in the preheated oven for 30 minutes.


Remove the foil, top the gratin with the remaining cheese, and place it back in the oven uncovered for an additional 30-40 minutes, or until bubbly, tender, and golden brown on top. If you like it a little extra-browned on top, set the oven to broil, and brown the top of the gratin for 1-2 minutes.


Remove from the oven, and allow to rest for 15 minutes before serving.