Creamy Sweet Potato Gratin

When it comes to indulgent comfort food, Creamy Sweet Potato Gratin takes center stage. This dish combines tender sweet potato slices with a rich, velvety béchamel sauce infused with garlic, herbs, and nutmeg. Topped with melted Parmesan and Gruyère cheeses, it’s the perfect side dish for family dinners or holiday feasts. Follow this step-by-step guide to create a gratin that’s as beautiful as it is delicious.

---

Why Sweet Potato Gratin?

Sweet potatoes offer a naturally sweet and earthy flavor, perfectly complemented by the savory richness of the creamy sauce and cheeses. This dish is versatile, pairing well with roasted meats like turkey, chicken, or lamb. It’s also a stunning addition to holiday tables, impressing guests with its elegant presentation and irresistible taste.

---

Ingredients

For the Béchamel Sauce:

• 3 tbsp butter
• 2 large shallots, finely diced
• 6 garlic cloves, minced
• 1 tbsp fresh thyme, chopped
• 1 tbsp fresh rosemary, chopped
• 3 tbsp all-purpose flour
• 2 cups whole milk
• 1 cup heavy cream
• 1½ tsp sea salt
• ½ tsp black or white pepper
• ⅛ tsp freshly grated nutmeg

For the Cheeses:

• 1½ cups grated Parmesan cheese, divided
• 1½ cups grated Gruyère cheese, divided

For the Sweet Potatoes:

• 4 to 5 medium sweet potatoes, peeled and thinly sliced (⅛-inch rounds)

---

Step-by-Step Instructions

1. Make the Béchamel Sauce

The béchamel sauce is the heart of this dish, adding creamy richness to the gratin. Here’s how to make it:

1. In a large sauté pan, melt the butter over medium heat.
2. Add the shallots and cook until tender and translucent, about 4 to 5 minutes.
3. Stir in the garlic, thyme, and rosemary, cooking until fragrant (about 30 seconds).
4. Sprinkle in the flour and stir until it’s absorbed into the butter, cooking for 1 minute to eliminate the raw flour taste.
5. Gradually add the milk, ½ cup at a time, whisking continuously until the sauce thickens before adding more.
6. Stir in the cream and season with salt, pepper, and nutmeg.
7. Simmer the sauce, then fold in 1 cup of Parmesan and 1 cup of Gruyère, whisking until the cheese melts into the sauce. Remove from heat.

---

2. Prepare the Sweet Potatoes

1. Peel and rinse the sweet potatoes under cold water to prevent discoloration.
2. Slice the sweet potatoes into ⅛-inch thick rounds using a mandolin or a sharp knife.
3. Stack the slices neatly for easy assembly.

---

3. Assemble the Gratin

1. Preheat the oven to 350°F (175°C). Line an oven-safe casserole dish with foil for easy cleanup.
2. Pour half of the béchamel sauce into the prepared dish, spreading it evenly.
3. Take stacks of sweet potato slices and arrange them neatly in the dish, fanning them slightly for a visually appealing presentation.
4. Pour the remaining sauce over the sweet potatoes, ensuring every slice is coated.
5. Cover the dish tightly with foil.

---

4. Bake the Gratin

1. Bake the gratin in the preheated oven for 1 to 1½ hours, or until the sweet potatoes are tender. Use a knife or toothpick to check for doneness.
2. Remove the foil and sprinkle the remaining ½ cup Parmesan and ½ cup Gruyère over the top.
3. Switch the oven to broil and broil for 5 to 8 minutes, until the cheese topping is melted and golden brown.

---

5. Serve and Enjoy

1. Let the gratin cool for about 30 minutes before serving. This resting time allows the sauce to set and makes slicing easier.
2. Serve the gratin alongside roasted chicken, turkey, lamb chops, duck, or ham for a hearty and elegant meal.

---

Tips for the Perfect Sweet Potato Gratin

1. Use a Mandolin: A mandolin slicer ensures evenly thin slices, which cook evenly and look professional.
2. Season Layers: Sprinkle a pinch of salt and pepper between sweet potato layers for extra flavor.
3. Fresh Nutmeg: Grating nutmeg fresh adds a subtle, warm undertone to the sauce.
4. Customize the Cheese: Experiment with other cheeses like Fontina or Asiago for a unique twist.

---

Perfect Pairings for Sweet Potato Gratin

This dish is versatile enough to pair with various entrees:

• Herb-Crusted Roast Chicken
• Glazed Ham with Pineapple
• Slow-Roasted Lamb Shanks
• Pan-Seared Duck Breast

For a vegetarian option, serve it alongside a crisp arugula salad with lemon vinaigrette or roasted Brussels sprouts.

---

Nutritional Highlights

While indulgent, this gratin also provides nutrients:

• Sweet potatoes are rich in beta-carotene and fiber.
• Cheese offers calcium and protein.
• Garlic and herbs provide antioxidants and flavor without extra calories.

---

Frequently Asked Questions

Can I make this ahead of time?

Yes! Assemble the gratin up to a day in advance and store it covered in the refrigerator. Bake it fresh before serving.

What’s a good substitute for Gruyère?

Fontina or Swiss cheese are great alternatives if Gruyère isn’t available.

Can I use regular potatoes instead of sweet potatoes?

Absolutely! Yukon Gold or Russet potatoes work well, though the flavor will differ.

---

Conclusion

Creamy Sweet Potato Gratin is the ultimate comfort food, combining the natural sweetness of sweet potatoes with the savory richness of a creamy, cheesy béchamel sauce. Whether it’s a holiday feast or a cozy family dinner, this dish delivers on flavor, presentation, and versatility. Try this recipe for your next gathering, and watch it become a new favorite!

Indulge in gourmet dining at home with our Cheesy Pull-Apart Christmas Tree Bread.

Print