This sweet potato gratin is the ultimate cozy side dish. Layers of tender sweet potatoes, melted Graviera (or Gruyère) cheese, and crispy prosciutto bake together into something irresistibly creamy, savory, and a little bit sweet. It’s simple to make, beautifully rustic, and perfect for any holiday table.
If you’re a fan of our delicious Sweet Potato Gratin, you’re in for a treat with our Fig Tart With Phyllo, Phyllo Cup Appetizers, and Roasted Cabbage with Bacon, Raisins, and Garlic!
Overview
Why you will love sweet potato gratin
New! A Greek Feast for the Holidays
A Greek Feast for the Holidays features 15 beautiful recipes crafted for a table that feels both luxurious and welcoming. From roasted turkey with herb butter and rich pork pot roast with winter fruit to golden lemon potatoes and syrup-drenched cakes, each dish celebrates Greek tradition, simplicity, and the joy of sharing.
Here is what you need.
- Sweet potatoes – Use any variety you like. Mixing red and purple sweet potatoes creates a gorgeous, colorful dish that looks stunning on the table.
- Graviera cheese (or Gruyère) – This nutty, slightly sweet cheese melts beautifully into the layers. If you can find Greek Graviera, give it a try, it’s a delicious Cretan version of Gruyère.
- Prosciutto cubetti – These small, thick cubes of prosciutto are perfect for this gratin and save you the trouble of cutting thin slices. They’re easy to find in most supermarkets. You can also substitute with pancetta or bacon for a similar savory kick.
- Butter – I prefer salted butter for extra flavor, but you can use your favorite.
- Heavy cream – Rich and luscious, it binds the layers together. For a lighter version, substitute half-and-half or whole milk.
- Eggs – Fresh, organic, and free-range if possible, always worth it for flavor and texture.
- Fresh sage and thyme – Classic holiday herbs that infuse the gratin with cozy, aromatic notes. Dried herbs work too if that’s what you have.
- Cloves and ground nutmeg – These warming spices add a subtle sweetness that makes the cream mixture smell like Christmas custard.
- Garlic – Just a touch adds depth and rounds out the flavors.
- Sea salt and freshly ground pepper – Essential for balancing the sweetness of the potatoes and the richness of the cheese.
Detailed measurements and instructions can be found on the recipe card at the bottom of the page.
How to make this sweet potato au gratin
- Preheat the oven to 400°F (200°C). In a medium pot, combine the cream, a few sage leaves, cloves, thyme sprigs, minced garlic, ground nutmeg, and a pinch of sea salt. Bring to a gentle simmer and cook for about 10 minutes, until slightly reduced and fragrant. Strain the mixture through a fine sieve to remove the herbs and cloves.
- In a large bowl, lightly whisk the eggs. Slowly pour in the warm cream while whisking constantly so the eggs don’t scramble. Mix well and set aside.
- Generously butter your baking dish (approximately 10.5″ x 7.5″). Sprinkle a little grated Graviera over the bottom to create a flavorful base. (image 1)
- Layer the sweet potatoes: Arrange a layer of thinly sliced sweet potatoes, slightly overlapping. Season with a pinch of salt and freshly ground pepper. Pour over ⅓ of the cream-egg mixture, then sprinkle ⅓ cup Graviera and 1 tablespoon prosciutto cubetti on top. (image 2)
- Repeat the layering process, adding potatoes, seasoning, cream mixture, cheese, and prosciutto two more times, ending with the final layer of potatoes, the remaining cream mixture, and toppings. (images 3-4)
- Cover the dish with a buttered sheet of foil and bake for about 40 minutes, until the potatoes are tender when pierced with a knife.
- Remove the foil, sprinkle the top with the remaining Graviera, and bake uncovered for another 25–30 minutes, until the gratin is golden brown and bubbling.
Suggestions & Substitutions
- Slice evenly: Use a mandoline or sharp knife to slice the sweet potatoes uniformly, this ensures they cook evenly and layer beautifully.
- Warm the cream gently: Don’t let it boil too hard; gentle simmering helps infuse the herbs and keeps the cream silky.
- Gruyère vs. Graviera: If you can find Greek Graviera, try it! It adds a distinct nutty flavor and a touch of Greek authenticity.
- Make ahead: Assemble the gratin a few hours before baking. Cover and refrigerate, then bake just before serving.
- For a crispier top: Broil for 2–3 minutes at the end, but keep an eye on it so it doesn’t burn.
- Let it rest: Give it 10–15 minutes after baking. This allows the custard to set and makes serving easier.
Serving suggestions
This sweet potato gratin makes a wonderful side dish for both everyday dinners and festive occasions. It’s rich, aromatic, and pairs beautifully with roasted meats and fresh salads.
- Holiday mains: Serve alongside roast herb butter turkey, pork pot roast, or roasted leg of lamb for a show-stopping holiday table.
- Simple pairings: It also complements grilled chicken skewers, baked salmon, or a crispy green salad with lemon vinaigrette for a lighter meal.
- Vegetarian spread: Skip the prosciutto for a meat-free version and pair it with roasted vegetables or a hearty lentil salad.
- Make it part of a Greek-style feast: Add maroulosalata, Greek lemon potatoes, and a savory cheese pie (tiropita) to create a full Mediterranean menu.
FAQs about ssweet potato au gratin
Storage and reheating
- Refrigerate: Store leftovers in an airtight container in the refrigerator for up to 3 days.
- Reheat: Warm individual portions in the microwave or reheat the whole dish in a 350°F (175°C) oven, covered with foil, until heated through (about 20 minutes).
- Avoid drying out: Add a splash of milk or cream before reheating to restore the creamy texture.
- Not ideal for freezing: The custard and cheese can separate once thawed, so this gratin is best made fresh or enjoyed within a few days.
More festive Greek dishes
Sweet Potato Gratin with Graviera
A rich, cheesy, sweet potato gratin with sage and thyme is sweet, savory & perfect for Thanksgiving.
Equipment
- 10.5" x 7.5" baking pan or gratin dish
Ingredients
- 6 medium sweet potatoes Sliced into 1/8-inch-thick rounds.
- 3 tablespoons butter softened
- 1.5 cups grated Graviera cheese or Gruyère cheese
- 4 oz prosciutto cubetti
- 2 cups heavy cream
- 3 tablespoons fresh sage chopped, or two teaspoon of dried sage
- 1 teaspoon ground nutmeg
- 1 tablespoon fresh thyme leaves or a teaspoon of dried thyme
- 3-4 cloves
- 4 garlic cloves minced
- 3 eggs lightly beaten
- salt
- freshly ground pepper
Instructions
- Heat oven to 400°F / 205°C.
- In a medium pot, bring cream, a few sage leaves, cloves, a couple of thyme sprigs, minced garlic, ground nutmeg, and a pinch of salt to a simmer. Simmer until reduced a little, about 10 minutes.When the cream mixture is ready pour it through a sieve to strain herb sprigs and cloves.
- In a large bowl, lightly whisk the eggs. Slowly pour the cream into the eggs; keep whisking while pouring. Mix well. Set aside.
- Butter a 10.5" x 7.5" baking pan or gratin dish.Sprinkle grated cheese all over the bottom of your pan.
- Place a layer of potatoes in the pan, slightly overlapping as you go.Sprinkle a pinch of salt and freshly ground pepper over sweet potatoes. Pour 1⅓ of the egg mixture—top potatoes with ½ cup Gruyère and 1 tablespoon of prosciutto.
- Repeat with another layer of potatoes, a small pinch of salt, freshly ground pepper and ⅓ egg mixture. Top again with ½ cup Gruyère and 1 tablespoon of prosciutto.
- Top with the last layer of potatoes, a small pinch of salt and freshly ground pepper, and the remaining egg mixture. Top again with 1/2 cup Gruyère and 1 tablespoon of prosciutto cubetti.Cover with a buttered foil sheet and bake until potatoes are tender, about 40 minutes.
- Remove foil, sprinkle top with remaining grated Gruyère.Bake until nicely browned and bubbling for 25-30 minutes. Let au-gratin cool a little and serve.
Notes
Nutritional Info – Please keep in mind that nutritional information provided is only an estimate and can vary based on products used.
Nutrition
Calories: 443kcalCarbohydrates: 15gProtein: 13gFat: 37gSaturated Fat: 22gCholesterol: 185mgSodium: 263mgPotassium: 304mgFiber: 2gSugar: 3gVitamin A: 9425IUVitamin C: 4mgCalcium: 384mgIron: 1mg
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Where is the prosciutto in the recipe? It’s not on the card and no mention of how to get individual tablespoons of prosciutto. Usually, prosciutto is cut very thin and so being able to measure a tablespoon would be very difficult.
Hi Benjamin,
Thank you for pointing that out, the recipe was updated recently and the prosciutto was left out by mistake. I use prosciutto cubetti which is pre-cut in small cubes /small slices, makes it easier to measure. I added a link for the product. I will put a note that a tablespoon is approximate.
Thank you again, hope you will enjoy the recipe.
x Jenny
Two of our favourite things… Sweet potato and gratin!!
Can’t wait to try this out, thanks for sharing.
Thanks so much, hope you will like it!
Flavorful. Nutmeg, Garlic and Herbs make a lovely combination. This dish looks creamy and cheesy and surely delicious. My weekend is going to be the best.
I didn’t know potato gratin could look so beautiful! This sounds divine!
Oh my goodness, this looks really good and tasty, I will definitely add this dish in our menu list. Thank you!
Turned out excellent. My brother loved it and asked for this recipe so he can make it again. I shared your page with him and now he’s a fan.
This recipe is amazing. Last night was actually the first time I made sweet potato gratin actually and I’m hooked! Before this I’d only made potato gratin. Oh and with this recipe I got to use my homegrown sage and thyme too. Just so delicious!
This gratin looks and sounds so flavorful! We would prefer it to the classic sweet version. The notes of Gruyère and prosciutto make it outstanding!
This is absolutely amazing! I make something similar every Christmas, but haven’t added prosciutto before. Definitely adding this to my holiday menu this year!
Hope you like it with prosciutto! Thanks so much!
I also wouldn’t care about turkey if I had this on my Thanksgiving table! Sounds like a great change from the usual scalloped potatoes. I love that you used prosciutto!
Thank you Erin!
This looks so tasty and easy to make! I can’t wait to try it out for Thanksgiving!
Hope you like it, Elena! Thanks so much, Jenny
Omg!! Made this for dinner tonight and its amazing!!! We loved it so much – will definitely be making it again!!!
Hi, Aline!
So happy you liked the au gratin.
Thank you! x Jenny
Can I make this ahead of time? Any instructions would be great!! this looks SOOOOOO GOOD!
Hi Kate!
It is really good!
You have two options:
1. You can prepare ahead, peel, and slice the potatoes the day before; store them in a ziplock bag in the fridge. You can simmer the cream mixture (don’t add the eggs) and grate the cheese the day before as well, storing them covered in the refrigerator. You assemble the rest the day of, bake as directed and serve.
2. Bake it for the first 40 minutes, let it cool, and refrigerate overnight. Next day let it come to room temp, add a couple of tablespoons of half and half or heavy cream on top and add grated cheese and reheat for about 40 minutes on a 350 F oven.
I will actually update the post and add these options, it’s a good idea.
Let me know how it came out!
Happy Holidays! x Jenny
Hi! This sounds amazing, I’ll be making this for tomorrow for Thanksgiving. Do I have to pre-cook the prosciutto cubetti Before adding it to the raw ingredients? Thank you!
Hi Nikki! You don’t have to precook the prosciutto, just use it as is. Happy Thanksgiving! X Jenny
Hello! Getting ready to make this for Thanksgiving. Can’t wait! I have a question… should the potatoes be peeled?
Hi Kathleen!
I leave the skin on and cut the sweet potatoes as thin as I can.
Thank you so much for making the gratin!
Let me know how it went.
Happy Thanksgiving!
x J