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Sweet Potato Gratin

This 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 thyme and a healthy dose of fresh-grated Parmesan. This is the breakfast, brunch, lunch or snack of champions. Make this recipe exactly as stated and your potatoes will turn out perfect. Enjoy our savory twist on sweet potatoes!

  • Servings 6-8 people
  • Dish Side
  • Time 2 hours
  • Skill Beginner



4 pounds sweet potatoes
2 ounces Gruyère cheese, finely grated
2 ounces Parmigiano-Reggiano (Parmesan) cheese, finely grated
1 medium head of garlic, finely chopped
2 1/2 cups heavy cream
2 sprigs fresh rosemary, finely chopped
Kosher salt, as needed
Black pepper, as needed
1 tablespoon whole butter




Preheat the oven to 400 degrees F/204 degrees C.

Peel sweet potatoes and cut into 1/8-inch slices using a mandoline slicer or a sharp knife.


In a large bowl, combine half of the grated cheese, all of the chopped garlic, cream and rosemary. Season with salt and black pepper. Add the sliced potatoes and toss. Be sure to separate any potatoes that are stuck together to ensure they are all covered evenly with the cream mixture.


Coat a 12-inch cast iron skillet with the whole butter. Stack the potatoes like a deck of cards on top of each other, then lay stacks on their sides in the skillet. Repeat this process until the potatoes form a ring around the outside and in the center of 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 a nice crust when the gratin bakes.


Once all the potatoes have been added, pour the remaining cream over the potatoes. Cover with aluminum foil and place inside of the preheated oven for 30 minutes.


Remove the foil and place it back inside of the oven uncovered for an additional 45 minutes. For the final 15 minutes of cooking, sprinkle the remaining cheese on the surface of the potatoes. Bake until golden brown. Remove from the oven and serve.