This Sweet Potato Gratin is rich, creamy, and irresistibly cheesy, featuring tender layers of sweet potatoes baked in a velvety Gouda and Parmesan cream sauce with fragrant garlic, fresh sage, and crunchy walnuts.
Every bite is perfectly balanced with savory, sweet, and nutty flavors, making it an elegant side dish for holiday dinners or cozy family meals.
Ingredients You’ll Need
- 2 lbs sweet potatoes peeled and sliced* (3–4 sweet potatoes)
- 2 tsp olive oil
- 1 Tbsp garlic finely minced
- 2 Tbsp fresh sage chopped
- 1 ½ cups heavy cream
- 1 cup water or chicken broth/vegetable broth
- 2 cups shredded Gouda cheese divided
- 1 cup shredded Parmesan cheese divided
- ½ tsp sea salt
- ½ tsp ground black pepper
- ⅓ cup walnuts finely chopped
This post may contain affiliate links.
How to Make Sweet Potato Gratin
1. Preheat the oven to 375°F.
2. Using a mandoline or a sharp knife, slice the sweet potatoes into thin, even rounds, no thicker than ⅛ inch.*
3. In a large saucepan over medium-low heat, warm the olive oil. Add the garlic and chopped sage, and cook for 1 to 2 minutes, or until fragrant, stirring frequently. Be careful not to let the garlic brown.
4. Stir in the water, heavy cream, sea salt, and black pepper. Cook gently for 1 to 2 minutes until warmed through.
5. Reserve 1 cup of the shredded Gouda, and ½ cup of the Parmasean cheese for the layers and topping. Add the remaining Gouda and the Parmesan cheese to the warm cream mixture, stirring until the cheeses have melted and the sauce is smooth.
6. Lightly grease a 9 x 13-inch baking dish or a large oven-safe skillet. Arrange a single layer of sweet potato slices in the bottom of the dish. Spoon some of the cheese sauce over the potatoes, then sprinkle with a portion of the chopped walnuts and a little cheese. Continue layering the potatoes, cheese sauce, cheese, and walnuts until all of the potatoes and sauce have been used.
7. Sprinkle the remaining Gouda & Parmesan cheeses evenly over the top. Cover the dish tightly with foil and bake for 30 minutes.
8. Remove the foil and continue baking for an additional 30 minutes, or until the sweet potatoes are tender, the cream has been absorbed, and the top is golden brown and bubbly.
9. Garnish with additional fresh sage and chopped walnuts, if desired. Serve hot and enjoy!
Sweet Potato Gratin with Gouda and Parmesan
Equipment
Ingredients
- 2 lbs sweet potatoes peeled and sliced* (3–4 sweet potatoes)
- 2 tsp olive oil
- 1 Tbsp garlic finely minced
- 2 Tbsp fresh sage chopped
- 1 ½ cups heavy cream
- 1 cup water or chicken broth/vegetable broth
- 2 cups shredded Gouda cheese divided
- 1 cup shredded Parmesan cheese divided
- ½ tsp sea salt
- ½ tsp ground black pepper
- ⅓ cup walnuts finely chopped
Instructions
- Preheat the oven to 375°F.
- Using a mandoline or a sharp knife, slice the sweet potatoes into thin, even rounds, no thicker than ⅛ inch.*
- In a large saucepan over medium-low heat, warm the olive oil. Add the garlic and chopped sage, and cook for 1 to 2 minutes, or until fragrant, stirring frequently. Be careful not to let the garlic brown.
- Stir in the water, heavy cream, sea salt, and black pepper. Cook gently for 1 to 2 minutes until warmed through.
- Reserve 1 cup of the shredded Gouda, and ½ cup of the Parmasean cheese for the layers and topping. Add the remaining Gouda and the Parmesan cheese to the warm cream mixture, stirring until the cheeses have melted and the sauce is smooth.
- Lightly grease a 9 x 13-inch baking dish or a large oven-safe skillet. Arrange a single layer of sweet potato slices in the bottom of the dish. Spoon some of the cheese sauce over the potatoes, then sprinkle with a portion of the chopped walnuts and a little cheese. Continue layering the potatoes, cheese sauce, cheese, and walnuts until all of the potatoes and sauce have been used.
- Sprinkle the remaining Gouda & Parmesan cheeses evenly over the top. Cover the dish tightly with foil and bake for 30 minutes.
- Remove the foil and continue baking for an additional 30 minutes, or until the sweet potatoes are tender, the cream has been absorbed, and the top is golden brown and bubbly.
- Garnish with additional fresh sage and chopped walnuts, if desired. Serve hot and enjoy!
Notes
- Use evenly sliced potatoes. A mandoline creates thin, uniform slices that cook evenly and produce the best texture.
- Choose the right Gouda. A young or smoked Gouda both work well. Smoked Gouda adds a rich, savory depth of flavor.
- Test for doneness. Insert a knife into the center of the gratin. It should slide in easily with little resistance.
- Let it rest. Allow the gratin to rest for 10 minutes before serving so the sauce can thicken slightly.
- Storage: Store leftovers in an airtight container in the refrigerator for up to 4 days.
- Reheating: Reheat covered in a 350°F oven for 15–20 minutes, or microwave individual portions until heated through.
- Freezing: Freeze baked and cooled gratin for up to 2 months. Thaw overnight in the refrigerator before reheating.
- Serving suggestions: Pair with roasted turkey, roast chicken, or a fresh green salad for a complete meal.
More Recipes You May Like: