Description
Creamy, Cheesy Sweet Potato Gratin
This rich and savory sweet potato gratin is perfect for your holiday table! A twist on the classic gratin, it combines layers of thinly sliced sweet potatoes with a velvety cheesy béchamel sauce infused with garlic, thyme, and rosemary. Topped with Gruyere and Parmesan, each bite is a burst of comforting flavors that pairs beautifully with roasted meats like turkey or lamb. Make your holiday meal unforgettable with this decadent side dish!
5-6 medium sweet potatoes
3 tbsp butter
2 large shallots, diced
6 garlic cloves, minced
1 tbsp fresh thyme
1 tbsp fresh rosemary, chopped
3 tbsp flour
2 cups whole milk
1 cup heavy cream
1 ½ cups Gruyere cheese, divided
1 ½ cups Parmesan cheese, divided
1 ½ tsp sea salt
½ tsp black pepper
⅛ tsp nutmeg
Directions:
1. Preheat oven to 350°F.
2. Make béchamel sauce by cooking butter, shallots, garlic, herbs, flour, milk, and cream.
3. Layer sweet potatoes and sauce in a casserole, bake for 1 hour.
4. Broil with cheese topping for 5-8 mins.
Prep Time: 30 mins
Kcal: 522 per serving
Step-by-Step Guide
1. Prep Ingredients: Peel the sweet potatoes and slice them uniformly 1/8-inch thick using a mandoline or sharp knife. Grate the Gruyere and Parmesan cheeses. Mince garlic, dice shallots, and chop fresh herbs.
2. Make the Béchamel: In a large saucepan over medium heat, melt the butter. Add shallots, cooking for 3-4 minutes until soft. Add garlic, thyme, and rosemary, cooking for 1 minute until fragrant. Whisk in the flour to form a paste (roux) and cook for 2 minutes. Gradually whisk in the milk and heavy cream until smooth. Bring to a gentle simmer, stirring constantly until thickened, about 5-7 minutes. Remove from heat. Stir in 1 cup of Gruyere and 1 cup of Parmesan until melted. Season with salt, pepper, and nutmeg.
3. Assemble the Gratin: In a greased 9×13 inch baking dish, spread a thin layer of the sauce. Arrange a single, slightly overlapping layer of sweet potato slices. Spoon a portion of the sauce over the potatoes, spreading evenly. Repeat layers, finishing with a final layer of sauce.
4. Bake: Cover the dish tightly with foil. Bake in the preheated 350°F oven for 50-60 minutes, or until the potatoes are tender when pierced with a knife.
5. Brown the Top: Remove the foil. Sprinkle the remaining 1/2 cup of each cheese over the top. Switch the oven to broil (high, if possible) and broil for 5-8 minutes, watching closely, until the top is golden brown and bubbly. Let rest for 15 minutes before serving.
Serving Suggestions
This gratin is a star holiday side dish. Serve it alongside a classic roasted turkey, honey-glazed ham, or herb-crusted prime rib. For a smaller gathering, pair it with pan-seared pork chops or roasted chicken. Balance its richness with simple, bright sides like a crisp green salad with a vinaigrette, roasted green beans, or honey-glazed carrots.
How-to Summary
Create this gratin by making a creamy, herb-infused cheese sauce (béchamel). Layer thinly sliced sweet potatoes with the sauce in a baking dish. Bake covered until the potatoes are tender. Uncover, top with remaining cheese, and broil until golden. Let rest before serving for the perfect slice.
Frequently Asked Questions
Can I make this gratin ahead of time? Yes. Assemble the dish completely, cover, and refrigerate for up to 24 hours. Add 10-15 minutes to the covered baking time since it will be cold. Add the final cheese topping just before broiling.
Can I use regular potatoes instead? Absolutely. Yukon Gold or Russet potatoes work wonderfully, though the flavor profile will be more traditional. Adjust baking time as needed.
What can I substitute for heavy cream? For a slightly lighter version, you can use half-and-half or even all whole milk, though the sauce will be less rich and may thicken slightly differently.
How do I store and reheat leftovers? Store cooled leftovers in an airtight container in the fridge for up to 4 days. Reheat portions in the microwave or cover the dish with foil and warm in a 325°F oven until heated through.
My sauce seems too thick. What should I do? If the béchamel becomes too thick before assembling, simply whisk in a splash of additional milk or cream until it reaches a pourable, gravy-like consistency.
Common Mistakes to Avoid
- Uneven Potato Slices: Inconsistent thickness leads to uneven cooking. Use a mandoline for uniform slices.
- Rushing the Roux: Not cooking the flour and butter mixture for a full 2 minutes can result in a raw, pasty flavor in the sauce.
- Adding Cheese to Boiling Sauce: Always remove the béchamel from heat before adding cheese to prevent it from becoming grainy or separating.
- Skipping the Rest: Cutting into the gratin immediately after baking will cause it to be soupy. Letting it rest for 15 minutes allows the sauce to set.
- Unwatched Broiling: The cheese topping can burn in seconds under the broiler. Stay close and monitor it constantly.
Conclusion
This Creamy, Cheesy Sweet Potato Gratin is more than a side dish; it’s a memorable centerpiece for your holiday table. By following the detailed steps and avoiding common pitfalls, you’ll achieve a dish with perfect layers, a velvety sauce, and a gloriously golden crust. Its balance of sweet, savory, and herbal notes is sure to impress your guests and become a requested tradition for years to come.