Name: Sweet Potatoes au Gratin with Gruyère, Parmesan, and Pecans Recipe
Prep time: 20 min
Cook time: 50 min
Total time: 1 h 10 min
Cuisine: French
Ingredients: 4 sweet potatoes (around 1400g); 1 tbsp butter; 1 shallot, finely minced; 1 clove garlic, minced; 3 sprigs fresh thyme; 350 ml heavy cream; 150 g grated Gruyere cheese; 20 g grated Parmesan cheese; 1 tsp nutmeg, freshly grated; Salt, to taste; Black pepper, to taste; 20 g roughly chopped pecans

Jump to Recipe· 4.3 from 68 reviews

If you’re craving a cozy dish that elevates humble sweet potatoes into something spectacular, you have to try this Sweet Potatoes au Gratin with Gruyère, Parmesan, and Pecans Recipe. It’s a luscious blend of creamy cheeses, aromatic herbs, and crunchy pecans baked to golden perfection, bringing out the natural sweetness and earthiness of the potatoes. This recipe hits every note – creamy, savory, nutty, and just a touch indulgent – perfect for holiday dinners or any time you want to impress without fuss.

Ingredients You’ll Need

In a black oval cast iron pan, there are many thin slices of orange sweet potatoes layered closely together in a spiral pattern, filling the pan from the edges toward the center. The slices have slightly browned spots and are sprinkled with small bits of green herbs and whole cloves of garlic peeking out between the layers. Next to the pan on a white marbled surface, there is a small metal bowl with a wooden brush resting inside it, and two green herb leaves lie beside the bowl. A crumpled light gray cloth is partially visible under the pan. Photo taken with an iphone --ar 4:5 --v 7

These ingredients are straightforward but carefully chosen to create layers of flavor and delightful textures in your Sweet Potatoes au Gratin with Gruyère, Parmesan, and Pecans Recipe. Each component, from the rich cheeses to the fresh thyme, complements the natural sweetness of the potatoes and provides balance throughout the dish.

Sweet potatoes (4, around 1400g): Choose firm, vibrant-skinned potatoes for a tender yet sturdy gratin base.
Butter (1 tbsp): Adds richness and helps sauté aromatics beautifully.
Shallot (1): Milder than onion, it infuses subtle sweetness and depth.
Garlic (1 clove): Enhances the savory flavor without overpowering the dish.
Fresh thyme (3 sprigs): Brings a herby brightness that cuts through the creamy texture.
Heavy cream (350 ml): Creates that indulgent, velvety sauce that hugs every potato slice.
Gruyère cheese (150 g, grated): Melts into a nutty, creamy layer essential for au gratin.
Parmesan cheese (20 g, grated): Adds sharpness and depth to the cheese topping.
Nutmeg (1 tsp): A warm spice that gently lifts the overall flavor profile.
Salt: Essential for enhancing the natural sweetness and balancing richness.
Black pepper: Adds just the right amount of spice to deepen the taste.
Pecans (20 g, roughly chopped): Deliver a delightful crunch and buttery nutty contrast on top.

How to Make Sweet Potatoes au Gratin with Gruyère, Parmesan, and Pecans Recipe

Step 1: Prepare the Sweet Potatoes

Begin by peeling and slicing the sweet potatoes into thin, even rounds about 1/8 inch thick, ensuring they cook evenly. This will give your gratin a perfect tender texture without becoming mushy.

Step 2: Sauté Aromatics

Melt the butter in a skillet over medium heat, add finely chopped shallots and minced garlic. Cook gently until softened and fragrant, about 3 minutes. Then, toss in your fresh thyme sprigs to release their savory aroma, which will subtly infuse the cream sauce later.

Step 3: Make the Cream Sauce

Pour the heavy cream into the skillet with the aromatics and thyme, reducing the heat to low. Stir in nutmeg, salt, and black pepper to taste, letting the flavors meld until the sauce thickens slightly, about 5 minutes. This sauce will ensure your potatoes are decadently moist and flavorful.

Step 4: Assemble the Gratin

Preheat your oven to 180°C (350°F). In a baking dish, layer half of the sweet potato slices, pour half the cream sauce over them, then sprinkle a generous amount of grated Gruyère and Parmesan. Repeat with the remaining potatoes and cream, finishing with cheese on top. This layering locks in moisture and flavor perfectly.

Step 5: Add the Crunch

Sprinkle the chopped pecans evenly over the top layer of cheese to add a wonderful textural contrast once baked. Pecans will toast slightly, enhancing their nutty fragrance and complementing the creamy dish beautifully.

Step 6: Bake to Golden Perfection

Place the dish in the oven and bake for 40-50 minutes, or until the top is golden brown and bubbling, and the sweet potatoes feel tender when pierced with a fork. Let it rest a few minutes before serving to set the creamy layers.

How to Serve Sweet Potatoes au Gratin with Gruyère, Parmesan, and Pecans Recipe

A collection of thinly sliced orange sweet potato rounds layered slightly overlapping on a white marbled surface, with a few whole and halved sweet potatoes around them. On the left side, there is a white mandoline slicer with a metal blade cutting one sweet potato. To the right of the slices is an old knife with a worn silver blade and a wooden handle resting on the white marbled surface. In the bottom right corner, there is a light gray fabric partially folded. The background is clear with a clean white marbled texture photo taken with an iphone --ar 4:5 --v 7

Garnishes

Brighten your beautiful gratin with a sprinkle of freshly chopped parsley or extra thyme leaves. These not only add a pop of color but also a fresh herbal note that balances the richness.

Side Dishes

This dish pairs wonderfully with roasted meats like turkey, ham, or pork tenderloin, as well as a crisp green salad or steamed seasonal vegetables. The creamy texture and nutty flavors of the gratin contrast delightfully with lighter, fresher sides.

Creative Ways to Present

For a stunning presentation, try using individual ramekins for personal servings or layer the gratin inside rustic ceramic dishes. Adding a few whole pecans on top before baking gives an artisanal touch that’ll impress your guests visually and flavor-wise.

Make Ahead and Storage

Storing Leftovers

Your Sweet Potatoes au Gratin with Gruyère, Parmesan, and Pecans Recipe will keep beautifully in the fridge for up to 3 days when covered tightly. Flavors tend to deepen after resting, so leftovers are often even better!

Freezing

For longer storage, cover the unbaked gratin tightly with plastic wrap and foil, then freeze for up to 2 months. To cook, thaw overnight in the fridge and bake as usual, adding extra time if needed for thorough heating.

Reheating

Reheat portions gently in the oven at 160°C (320°F) until warmed through, around 15-20 minutes. This helps preserve the texture without drying out the creamy sauce or burning the nut topping.

FAQs

Can I use regular potatoes instead of sweet potatoes?

Absolutely! While this recipe shines with sweet potatoes, regular white potatoes can also be used. Keep in mind the flavor will be less sweet, so you might want to adjust seasoning accordingly.

What can I substitute for Gruyère cheese?

If Gruyère isn’t available, Swiss cheese or Emmental are great alternatives, as they melt well and have a mild, nutty flavor that complements the dish.

Are pecans necessary?

While not mandatory, pecans add a lovely crunch and buttery richness that contrasts beautifully with the creamy potatoes. Walnuts or almonds could work as a substitute if desired.

Can I make this dish vegan or dairy-free?

This recipe relies on dairy for its signature creaminess, but you can experiment with plant-based creams and cheeses. However, the flavor and texture will differ, so it might require some trial and error.

How thin should I slice the sweet potatoes?

The slices should be about 1/8 inch thick to ensure even cooking and delicate layers that meld together nicely without being too soft or mushy.

Final Thoughts

There’s something truly special about Rich Sweet Potatoes au Gratin with Gruyère, Parmesan, and Pecans Recipe that makes everyone feel cozy and indulgent. I encourage you to try this dish — it’s easier than it looks, yet it brings gourmet-level delight right to your table. Whether it’s for a festive occasion or a comforting weeknight meal, this gratin will quickly find a cherished spot in your recipe rotation.