Made with thinly sliced sweet potatoes baked in a creamy béchamel sauce, this Sweet Potato Gratin is the most luxurious way to serve sweet potatoes. The tender pieces of sweet potatoes plump up in the creamy sauce while a crunchy crust of cheesy goodness develops on the outside. It tastes like fall in every bite and is a fun alternative to traditional au gratin potatoes for any occasion!
Potatoes au gratin is one of the most beloved potato dishes, commonly served at all the major holiday meals. This cheesy sweet potato gratin recipe follows this same tradition, but believe me when I tell you that sweet potatoes are a major upgrade. They're still tender and creamy, but that hint of sweetness makes the whole dish way more interesting. This easy sweet potato gratin will be right at home next to Holiday Glazed Baked Ham, Roast Turkey, and all your favorite Thanksgiving sides. It's the perfect side dish!
Why You'll Love This Sweet Potato Gratin
- The ultimate comfort food. The sweet potato slices essentially soak up the creamy sauce, which you can taste with every bite. I'm not sure there is a more perfect comfort food out there. This dish has it all — warm, cozy, rich, hearty, and filling. I could eat it with a spoon!
- Perfect for Thanksgiving dinner. Many of us serve Potatoes Au Gratin or Scalloped Potatoes around the holidays, and this sweet potato au gratin is the perfect alternative. It fills that spot so well while offering a fun twist on a traditional flavor profile.
- Savory recipe for sweet potatoes. Many of us associate sweet potatoes with brown sugar and marshmallows around the holidays, but I love that this savory sweet potato gratin melds sweet and savory together. It's still sweet from the potatoes, but you get so much flavor from that creamy, cheesy sauce!
Ingredient Notes
To make this delicious Sweet Potato Gratin, you will need the following ingredients (full measurements in recipe card below):
- sweet potatoes - peeled and thinly sliced. It's much easier to do this with a mandolin slicer as you need really consistent slices.
- butter
- garlic - this will help make this sweet potato gratin taste more savory.
- heavy cream - for a rich, creamy sauce. Half and half will work in a pinch, but I prefer the richness of heavy whipping cream over whole milk.
- cheese - use shredded Gruyère cheese or sharp cheddar cheese, and Parmesan, for the cheese sauce. You can also use a mix of different types of melty cheese.
- salt and pepper
- thyme - finely chopped to add to the sauce and as a garnish.
You will also need measuring cups and spoons, 9x13 baking dish, mandolin slicer, medium saucepan, and aluminum foil.
How to Make the Best Sweet Potato Gratin
- Slice sweet potatoes. Use a mandolin to slice sweet potatoes into ⅛ inch thick rounds.
- Make sauce. In a medium saucepan, melt butter over medium heat and sauté garlic until fragrant, about 1-2 minutes. Add heavy cream, salt, pepper, cheese, and thyme. Stir constantly until the melted cheese mixture is smooth, about 3-5 minutes.
- Assemble. Lightly grease a 9x13-inch casserole dish with butter or cooking oil spray. Arrange sliced sweet potato rounds in an even layer in the baking dish. Pour cheese sauce on top of the sweet potatoes, and cover with aluminum foil.
- Bake. Place into a 375F preheated oven and bake for 45 minutes. Uncover and continue to bake for 20-30 more minutes or until golden brown and the sweet potatoes are tender.
- Broil (optional). Optionally broil on HI for an additional 1-2 minutes to achieve a lightly brown crust.
- Serve. Garnish with fresh chopped thyme and serve immediately.
Recipe Variations
- Add a crunchy breadcrumb topping. For a crispy layer, feel free to mix together bread crumbs with melted butter like this Baked Mac and Cheese. The extra crunch is a nice way to balance the cream sauce and tender pieces of sweet potato.
- Try other herbs. I love the flavor of thyme with gruyere cheese, but you really just need some sort of fresh herbs to bring the dish to life. This recipe also works well with fresh sage or rosemary.
- Mix and match potatoes. For a slightly less sweet side dish, alternative slices of sweet potato and regular potatoes, ideally Yukon Gold or Russet potatoes.
How to Serve
This Sweet Potato Gratin is a delicious side dish that goes well paired with some of my favorite sides including:
- Prime Rib Roast
- Baked Chicken Drumsticks
- Instant Pot Turkey Roast
- Roasted Pork Tenderloin
- Salmon Bites
- Air Fryer Lamb Chops
Recipe Tips and Tricks
- Grease the pan. If you want to simplify clean-up and serve picture-perfect portions, add the sweet potatoes to a well greased baking dish.
- Grate the cheese yourself. Many grated cheeses are coated with a fine powder to keep them from clumping together in the bag. This can affect how well they melt. For the gooiest, meltiest cheese sauce, grate the cheese yourself.
- Embrace the broil. Taking a few minutes to broil the top of this delicious sweet potato gratin is well worth the minimal effort. You'll get a bubbly, golden brown crust but crispy, cheesy edges It's the best part!
Storing and Freezing Instructions
How to Store
Allow the dish to cool to room temperature, then either transfer the leftovers to an airtight container or cover the full baking dish with plastic wrap or foil. Refrigerate for 3-4 days.
How to Reheat
Smaller portions can be microwaved for 1-2 minutes or you can cover the pan with foil and bake at 350 F until heated through.
How to Freeze
Leftovers can be frozen for up to 3 months, although the consistency will be softer and a little mushier after thawing and reheating.
FAQ
Yes! Prepare the whole dish, cover it with foil, then refrigerate it overnight and bake it the next day, right before your meal. This is a great way to save a little time on the day while still serving an exceptional Thanksgiving or Christmas dinner.
This sweet potato au gratin recipe is a savory dish made by baking thin slices of sweet potato in a creamy cheese mixture while sweet potato casserole is a sweet side dish usually served with butter, brown sugar, and marshmallows. They are both great holiday side dishes, but one tastes much more like dessert!
Yes, and I think you might fall in love with this flavor combination. Especially if you choose salty, nutty cheeses that pair well with the sweetness of sweet potatoes, you get a uniquely cozy, comforting side dish fit for any special occasion. Plus, sweet potatoes tend to cook a little faster than white potatoes, too!
More Sweet Potato Recipes
- Sweet Potato Casserole with Marshmallows
- Smashed Sweet Potatoes
- Sweet Potato Tater Tots
- Baked Sweet Potato
- Herb Roasted Sweet Potatoes
- Sweet Potato Croquettes
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Recipe
Sweet Potato Gratin
- Total Time: 1 hour 20 minutes
- Yield: 8-10 servings
- Diet: Vegetarian
Description
Made with thinly sliced sweet potatoes baked in a creamy béchamel sauce, this Sweet Potato Gratin is the most luxurious way to serve sweet potatoes. The tender pieces of sweet potatoes plump up in the creamy sauce while a crunchy crust of cheesy goodness develops on the outside. It tastes like fall in every bite and is a fun alternative to traditional au gratin potatoes for any occasion!
Ingredients
- 2 ½ pounds sweet potatoes, peeled and thinly sliced (⅛ inch thick)
- 2 tablespoons unsalted butter
- 2 cloves garlic, minced
- 1 ½ cups heavy cream
- ½ teaspoon salt
- ¼ teaspoon ground black pepper (or to taste)
- 1 ½ cups Gruyère cheese or sharp cheddar, shredded
- ¼ cup Parmesan cheese, shredded
- ½ teaspoon fresh thyme, finely chopped
Instructions
- Preheat oven to 375 F. Lightly grease a 9x13-inch casserole dish with butter or cooking oil spray.
- Use a mandolin to slice sweet potatoes into ⅛ inch thick rounds. Arrange sliced sweet potato rounds in an even layer in the baking dish.
- In a medium saucepan, melt butter over medium heat and sauté garlic until fragrant, about 1-2 minutes. Add heavy cream, salt, pepper, cheese and thyme. Stir constantly until the melted cheese mixture is smooth, about 3-5 minutes.
- Pour cheese sauce on top of the sweet potatoes, and cover with aluminum foil.
- Place into the oven and bake for 45 minutes. Uncover and continue to bake for 20-30 more minutes or until golden brown and the sweet potatoes are tender.
- Optionally broil on HI for an additional 1-2 minutes to achieve a lightly brown crust.
- Garnish with fresh chopped thyme and serve immediately.
Notes
How to store: Allow the dish to cool to room temperature, then either transfer the leftovers to an airtight container or cover the full baking dish with plastic wrap or foil. Refrigerate for 3-4 days.
How to reheat: Smaller portions can be microwaved for 1-2 minutes or you can cover the pan with foil and bake at 350 F until heated through.
How to freeze: Leftovers can be frozen for up to 3 months, although the consistency will be softer and a little mushier after thawing and reheating.
- Prep Time: 15 minutes
- Cook Time: 1 hour 5 minutes
- Category: Side Dish
- Method: Bake
- Cuisine: American
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