Sweet Potato Gratin is a warm, cozy dish that fills the house with cinnamon and butter-scented steam. This simple family side checks the boxes for comfort, ease, and a little holiday glow, whether you want a weeknight winner or a dish for guests. If you like rich, creamy layers, you might also enjoy our best sweet potato casserole for another take on sweet spuds.

Why Make This Recipe

Quick & Easy: Slices bake in one dish with simple steps.
Family Favorite: Mild sweet notes and creamy cheese please kids and adults.
Budget-Friendly: Mostly pantry staples and one vegetable make it affordable.

This gratin stands out because the sweet potato slices soften but keep a little bite, and the top turns golden and slightly crisp. It brings comfort and a warm, nostalgic feeling—like a cozy dinner table where everyone reaches for seconds. If you want a heartier main to pair it with, try a savory twist like our chicken sweet potato curry.

Ingredients

For the gratin

3 pounds sweet potatoes, peeled and sliced 1/8–1/4 inch thick (about 4 medium)
2 cups heavy cream or half-and-half
2 garlic cloves, minced
1 teaspoon salt
1/2 teaspoon black pepper
1/4 teaspoon ground cinnamon (optional, for warmth)

For the cheese topping

1 1/2 cups grated Gruyère or sharp cheddar
1/2 cup grated Parmesan (for extra savory crust)
2 tablespoons unsalted butter, melted (for dotting on top)

Helpful notes:

Use unsalted butter so you control the salt level.
If you prefer a lighter dish, use half-and-half instead of heavy cream.

How to Make Sweet Potato Gratin

Preheat your oven to 375°F (190°C). Butter a 9×13-inch baking dish. Preheating ensures even cooking and a golden top.
Thinly slice the peeled sweet potatoes. Aim for even slices so they cook the same. A mandoline helps but a sharp knife works fine.
In a medium saucepan, warm the cream with minced garlic, salt, pepper, and cinnamon over low heat until it just begins to steam. Do not boil — this keeps the cream smooth and prevents separation.
Arrange a single layer of sweet potato slices in the bottom of the dish, slightly overlapping. Sprinkle a little of the Gruyère and Parmesan over the layer. Repeat layers until you use all potatoes, finishing with cheese on top. Layering creates pockets of melted cheese and creamy potato.
Pour the warm cream mixture evenly over the layered potatoes, pressing gently so the cream settles between slices. This step makes sure every slice absorbs the cream and becomes tender.
Dot the top with melted butter and a final sprinkle of Parmesan. The butter helps the top brown nicely.
Cover the dish loosely with foil and bake for 30 minutes. Remove foil and bake another 20–30 minutes, until the top is golden and a knife slides through the potatoes easily. Baking covered first steams the potatoes; uncovering lets the top crisp.
Let the gratin rest 10 minutes before serving so it firms up and slices cleanly.

How to Serve Sweet Potato Gratin

Serve warm in slices straight from the dish, garnished with a few fresh thyme sprigs or chopped parsley for color.
Pair with roasted chicken or pork and a simple green salad to balance the richness.
For a holiday table, place the gratin in the center and let guests spoon onto plates family-style.

How to Store Sweet Potato Gratin

Fridge: Cool completely, then cover tightly or store in an airtight container for up to 4 days.
Freezer: Freeze in a sealed, freezer-safe container for up to 2 months. Thaw overnight in the fridge before reheating.
Reheat: Warm portions in a 350°F (175°C) oven for 15–25 minutes until hot and bubbly. For single slices, microwave 1–2 minutes, then crisp in a hot skillet or under the broiler for a minute if you like a crunchy top.

Tips to Make Sweet Potato Gratin

Slice evenly for uniform cooking; use a mandoline if you have one.
Warm the cream before pouring — cold cream can slow baking and leave firmer centers.
Don’t skip the rest time; it helps the gratin hold together for neat slices.
Taste the cream mix before pouring to adjust salt and spice.
For a deeper flavor, swap half the Gruyère for sharp cheddar.

Variation

Gluten-free: This recipe is naturally gluten-free if your cheeses and other ingredients are labeled gluten-free.
Maple-brown sugar twist: Stir 1–2 tablespoons of maple syrup and a pinch of brown sugar into the cream for a sweeter, autumn-style gratin.

FAQ: Can I use regular potatoes instead of sweet potatoes?

Yes. Regular Yukon Gold or Russet potatoes will work. You may need a slightly longer bake time (about 10–15 minutes more) because they take longer to soften.

FAQ: How do I avoid a watery or soggy gratin?

Slice potatoes evenly and warm the cream before pouring. Baking covered first, then uncovered, helps steam them through while letting excess moisture reduce when uncovered.

FAQ: Can I make this ahead for a dinner party?

Absolutely. Assemble and refrigerate (covered) up to 24 hours before baking. Add 10–15 minutes to the covered baking time if baking straight from the fridge.

Conclusion

This Sweet Potato Gratin brings warm, creamy comfort to any meal. The soft, slightly sweet slices and the golden, cheesy top make it a simple crowd-pleaser that feels special without fuss. If you want extra inspiration or a slightly different take, check out this lovely recipe for Sweet Potato Gratin – The Perfect Holiday Side Dish! Try it, leave a comment and a star rating to tell us how it went, and please share your favorite photo on Pinterest or Facebook. What twist did you try? Let us know below!