Description
This Sweet Potato Gratin is a deliciously creamy and cheesy side dish perfect for fall and winter. Layers of thinly sliced sweet potatoes are baked with Gouda, Parmesan, fresh thyme, and a rich cream mixture, resulting in a beautifully golden, flavorful gratin that's sure to impress at any meal.
Ingredients
Sweet Potatoes
- 3 large sweet potatoes, peeled and sliced ⅛ inch thick on a mandoline (about 2 pounds)
Cheeses & Herbs
- ½ cup Parmesan cheese, shredded
- 1 ½ cups shredded Gouda cheese (such as Roth Gouda wedges)
- 1 teaspoon fresh thyme, roughly chopped
Dairy
- ¾ cup milk
- ¾ cup heavy cream
Seasonings
- Kosher salt, to taste
- Freshly ground black pepper, to taste
Instructions
- Preheat and Prepare Skillet: Preheat your oven to 400°F (200°C) and lightly grease a cast iron skillet to prevent sticking.
- Mix Cream and Milk: In a bowl, combine the heavy cream and milk, mixing well. Set this cream mixture aside for layering.
- Layer Sweet Potatoes: Arrange a layer of the thinly sliced sweet potatoes evenly in the skillet. Drizzle a few tablespoons of the cream mixture over the potatoes. Season with kosher salt, freshly ground black pepper, and sprinkle some chopped thyme and a portion of both cheeses evenly. Repeat this process to create 6 to 8 layers, pressing down firmly to submerge the potatoes in the cream mixture and ensuring even seasoning between layers.
- Top and Cover: Once all layers are set, add extra cheese on top if desired. Cover the skillet to help cook the potatoes evenly and retain moisture during baking.
- Bake Covered: Place the covered skillet in the preheated oven and bake for about 30 minutes, allowing the potatoes to begin softening and the cream to infuse the dish.
- Uncover and Finish Baking: Remove the cover and continue baking for an additional 30 to 45 minutes. During this time, the cream should be mostly absorbed, the sweet potatoes fully cooked, and the top should become beautifully browned and bubbly.
- Rest Before Serving: Remove the gratin from the oven and let it rest for 15 minutes to set and cool slightly, making it easier to serve and enhancing the flavor.
Notes
- You can prepare this gratin ahead of time by assembling it and baking it covered for 30 minutes (par-baking). After that, allow it to cool to room temperature, cover, and refrigerate overnight. When ready to serve, bake it further until fully cooked and warmed through.
- Using a mandoline to slice the sweet potatoes ensures even cooking and a uniform texture.
- For a richer flavor, consider using full-fat dairy products and freshly shredded cheeses.
- Adjust seasoning as needed to suit your taste, particularly salt and pepper.