Description

This Creamy, Cheesy Sweet Potato Au Gratin recipe offers a comforting twist on the classic gratin by using sweet potatoes layered with a rich garlic-infused cream sauce and a blend of Gruyere, Gouda, and Parmesan cheeses. Perfectly baked to golden perfection, it combines fresh thyme and aromatic garlic for a decadent, savory side dish that’s ideal for holiday meals or cozy dinners.

Ingredients

Scale

Sweet Potatoes

3 sweet potatoes, sliced 1/8 inch thick on a mandolin slicer

Sauce

1 3/4 cups heavy cream
4-5 cloves garlic, minced
2 tbsp unsalted butter, melted
Salt and pepper, to taste

Cheeses

1 1/2 cups Gruyere cheese, shredded
1/2 cup Gouda cheese, shredded
1/2 cup Parmesan cheese, shredded

Herbs

2 tbsp fresh thyme

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Instructions

Preheat Oven: Preheat your oven to 375°F (190°C) to prepare for baking the gratin.
Prepare Cream Sauce: In a saucepan over medium heat, melt the butter. Add the minced garlic and sauté for 1-2 minutes until fragrant. Pour in the heavy cream, then season with salt and pepper. Heat the mixture for a couple more minutes; it will not thicken much here but will thicken as it bakes due to starch release from the potatoes.
Layer Sweet Potatoes: Lightly grease a baking dish. Begin layering the sweet potato slices evenly in the dish. Season each layer with salt, pepper, and fresh thyme, and sprinkle a mixture of the shredded Gruyere, Gouda, and Parmesan cheeses over each layer. Repeat to create 3-4 layers, ensuring each layer is well coated but without excessive sauce.
Add Cream Mixture: Pour the prepared cream and garlic mixture over each layer of sweet potatoes, ensuring even coverage throughout the dish.
Top and Cover: Sprinkle any remaining cheese mixture evenly over the top layer. Cover the dish tightly with aluminum foil to retain moisture while baking.
Bake Covered: Bake in the preheated oven for 45 minutes with the foil on. This allows the potatoes to cook thoroughly and begin softening.
Bake Uncovered: Remove the foil, then continue baking for an additional 15-20 minutes until the sweet potatoes are tender and the top is golden brown and bubbling, indicating the cheeses have melted beautifully and formed a crust.
Serve: Let the gratin cool for a few minutes before serving to set slightly and enhance flavor melding. Enjoy as a rich side dish to your favorite main courses.

Notes

This recipe replaces traditional white potatoes with sweet potatoes for a slightly sweet and nutrient-rich version of the classic au gratin.
The combination of Gruyere, Gouda, and Parmesan offers complex and rich cheesy flavors with great melt and crust development.
Fresh thyme and garlic add aromatic depth and freshness that balances the richness.
Use a mandolin slicer to ensure even sweet potato slices for uniform cooking.
Covering the dish during the initial bake helps trap steam and soften the potatoes before crisping the top uncovered.
Perfect for holiday gatherings, Thanksgiving, or cozy fall and winter dinners.

Nutrition

Serving Size: 1 serving
Calories: 306 kcal
Sugar: 4 g
Sodium: 306 mg
Fat: 24 g
Saturated Fat: 15 g
Unsaturated Fat: 7 g
Trans Fat: 0.1 g
Carbohydrates: 13 g
Fiber: 2 g
Protein: 11 g
Cholesterol: 76 mg