This savory Sweet Potato Gratin is inspired by Pommes Anna, a French dish of creamy, thinly sliced potatoes with rich buttery flavor topped with melted Gruyere cheese.
Savory Sweet Potato Gratin
There’s no milk or cream in this sweet potato gratin, yet the texture is so buttery and creamy while keeping it as low-calorie as possible. Instead of a saucy gratin with loads of cream and calories, these sweet potatoes are thinly sliced like Pommes Anna and topped with cheese to make it a classic gratin. I love the texture of the super-thin potatoes, and the leftovers are even better. For more gratin recipes, try my Spinach Gratin and Brussels Sprouts Gratin.
Why This Sweet Potato Au Gratin Recipe Works
Gratin is a term for a dish with a breadcrumb or cheese topping that’s baked until crispy. Potato Gratin is the most popular, but there are many variations with different vegetables, like this Fennel Gratin, Butternut Squash Gratin, and Spinach Gratin. Here’s why this version with tender sweet potatoes works so well.
- Lighter than most gratins. This sweet potato gratin without cream or milk still gets nice and creamy in the oven. There’s just enough butter to taste it and make the dish rich.
- Prep ahead. You can make most of this dish beforehand, so you have less to do on Thanksgiving. Keep reading for my tips for making it in advance!
- Oven to table. It’s a beautiful dish that can go from the oven to the table. Slice it like a pie and let everyone serve themselves.
Ingredients You’ll Need
Here are the ingredients you’ll need to make this easy sweet potato gratin recipe. See the recipe card below for the exact measurements.
- Sweet Potatoes: Peel two pounds of sweet potatoes and slice them as thinly as possible. I cut them to 1/8-inch thick with a mandolin while wearing a cut-resistant glove.
- Butter: Melt two tablespoons of butter.
- Freshly chopped thyme leaves add a savory, peppery flavor that complements the sweet potatoes and cheese.
- Salt and pepper to season the potatoes.
- Cheese: Grated Parmesan and Gruyere cheese.
How to Make Sweet Potato Gratin
Follow the step-by-step instructions below to make the best sweet potato gratin from scratch.
- Coat the Potatoes with melted butter and season with thyme, salt, and pepper.
- Layer the Potatoes in a gratin or pie dish, pressing them down to keep them at an even thickness.
- Sprinkle both cheeses evenly over the top.
- Bake the Gratin: Spray a piece of foil with oil and cover the pan with it, oiled-side down. Bake the gratin for 30 minutes at 425°F, uncover, and bake for another 15 minutes until the potatoes are tender and the cheese is melted.
Watch How to Make This Recipe
Variations
- Herbs: Swap thyme with rosemary or sage.
- Potatoes: Substitute Yukon Gold potatoes.
- Cheese: Switch out the Parmesan with Pecorino Romano or Gruyere with Swiss.
What to Serve with Sweet Potatoes Gratin
This easy sweet potato gratin would be a perfect Thanksgiving and Christmas side dish, or just a regular weeknight dinner with your favorite protein and vegetable side.
Holiday Dishes
Sweet potato gratin makes the best addition to a holiday dinner menu.
Proteins
Try one or more of these delicious dinners on a weeknight.
Vegetable Sides
Round out your meal with any of these easy vegetable dishes.
Make Ahead Tip
If you’re hosting Thanksgiving, Christmas, or any dinner, you can prep most of this dish ahead of time to make the holiday less stressful.
- The day before, bake the dish without the cheese for 30 minutes. Let it cool and refrigerate it.
- When you’re ready to reheat it, cover it with foil and bake until warm.
- Top with cheese and bake for 15 minutes.
How to Store Gratin
Store potato gratin in an airtight container for up to 4 days in the refrigerator or 3 months in the freezer. Microwave leftovers until warm.
More Sweet Potato Recipes You’ll Love
- Mashed Sweet Potato Brulee
- Roasted Sweet Potatoes
- Sweet Potato Casserole with Praline Topping
- Mashed Sweet Potatoes
- Twice Baked Sweet Potatoes
Sweet Potato Gratin Recipe
Ingredients
- Olive oil spray
- 2 pounds sweet potatoes
- 2 tablespoons melted butter
- 1 tablespoon fresh thyme leaves, chopped
- 1 teaspoon kosher salt
- Fresh black pepper
- 1 ounce finely grated Parmesan cheese
- 3/4 cup grated Gruyere cheese
Instructions
- Preheat the oven to 425°F. Coat a round pie dish or other 6-cup gratin dish with olive oil spray.
- Peel the sweet potatoes and slice them as thinly as you can manage, I did them 1/8th inch thick with a mandolin. Put the slices in a large bowl and add the melted butter, thyme, salt, and pepper to taste. Toss to make sure all the slices are well coated.
- Take a handful of potatoes and arrange them in a layer on the bottom of the baking dish. Keep adding more layers, one handful of potatoes at a time and as you work, press the potato slices down and try to keep them in an even thickness all around. Once all the slices have been added, press down gently to compact them a bit.
- Sprinkle the Parmesan cheese and Gruyere evenly over the top. Spray one side of a piece of aluminum foil with olive oil spray and cover the pan with aluminum foil, oiled-side down (to prevent the cheese from sticking).
- Bake the gratin for 30 minutes. Uncover and continue to bake until the potatoes are tender when pierced with a knife and the cheese is melted, about 15 minutes.
- Let it rest for 5 minutes before slicing and serving.
Delicious & easy.
Excellent addition to our Christmas dinner this year. Didn’t have fresh thyme so I subbed fresh rosemary. Will definitely make again!
I subbed regular yukon gold potatoes for sweet potatoes. very tasty outcome but found needed garlic salt which made it perfect.
Love this! Delicious! Thank you , Gina!
So happy you enjoyed it!
Amazing. Made this for an early Christmas dinner. Will definitely be made again!
This is the best Sweet potato gratin recipe I’ve tried. I thought I just didn’t like cheese and sweet potatoes. This is great. I’ll definitely make it again.
Is there a vegan alternative? My daughter can’t have dairy cheese, but I’d really like to make this!
Excellent side with ham! Will make again!
Vegan cheese
Can you make this ahead of time then bake later?
Yes. There are directions in the narrative. 🙂
I think I’d like to try this with butternut squash.
Your Sweet Potato Gratin recipe is delicious! I made it for a Thanksgiving dish and it was a hit. Thank you so much for sharing all your wonderful recipes!
Tried this for Thanksgiving and it was fantastic! The grocery store was out of gruyere so I subbed Gouda. I doubled it in a 13×9 pan and it was perfect. Only enough leftovers for me to have for breakfast this morning 🤣 10/10 would recommend!
Made this last night for dinner. It was so good! We used gouda (not smoked) and parmesan since that’s what we had on hand. Will definitely make this again.