Twice-Baked Sweet Potato Gratin

Sweet Potato gratin in ramekins.

For the longest time, I didn’t like sweet potatoes.  I bypassed them at the market and snubbed them on restaurant menus.   I think my aversion to this particular tuber were those sweet potato casseroles that were piled with marshmallows and set under the broiler to turn the fluffy topping to a molten goo.  I know most people gravitate toward that kind of excess, but I prefer a more savory side.   Enter the twice-baked sweet potato gratin.

baked sweet potatoes
bake for an hour

And I promise these gratins are just as decadent as those sugary-topped casseroles, but instead of flamed marshmallows, it’s melty gruyere.  Instead of brown sugar and nutmeg, it’s fresh rosemary and black pepper.  

scoop flesh from sweet potatoes
scoop out the flesh

Best of all — it couldn’t be easier to make.  Bake the potatoes for an hour, then scoop out the soft flesh.  Use a potato ricer or hand mixer to mash the spuds and add a pat of butter, a little milk, some freshly chopped rosemary, salt and pepper to the mix.

mash sweet potatoes
sweet potato with herbs and butter

Stir in most of the cheese but save a little to sprinkle on top.  Then it’s into the oven for a second bake and 2-3 minutes under the broiler for a nice golden color. 

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sweet potato with cheese
Twice-Baked Sweet Potato Gratin with cheese in ramekin

If you’re a sucker for those long cheesy strands of goodness, you won’t be disappointed here.  One forkful and you’ll be swooning.  

Twice-Baked Sweet Potato Gratin with spoon and napkin
Twice-Baked Sweet Potato Gratin with fresh rosemary

More casserole and gratin side dishes you’ll love:


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4.18 from 17 votes

Twice-Baked Sweet Potato Gratin

Not your average sweet potato casserole – this one is rich with gruyere cheese and nary a marshmallow in site!
Author: Lisa Lotts
Course Side Dish
Cuisine American
Keyword gruyere, sweet potato
Prep Time 20 minutes
Cook Time 1 hour 25 minutes
Total Time 1 hour 45 minutes
Servings 6


  • 1 ½ pounds sweet potatoes
  • 1 teaspoon rosemary chopped fresh
  • ½ teaspoon kosher salt
  • ¼ teaspoon black pepper freshly ground
  • ¼ cup milk
  • 1 tablespoon butter
  • 1 ½ cups gruyere cheese shredded, divided


  • Preheat the oven to 375 degrees.
  • Place the potatoes on a baking sheet lined with aluminum foil and bake for 45 minutes to an hour – or until potatoes are cooked through. Remove from oven and cut each potato in half. Let the potatoes cool until you can handle them, then scoop out the flesh into a bowl.
  • Use a potato ricer or hand mixer to puree the potatoes. Stir in the rosemary, salt and pepper. Add the milk and butter and stir until butter has melted. Add 1 1/4 cups of gruyere and stir to combine. Set aside.
  • Spray 6 half-cup ramekins with vegetable spray. Divide the sweet potatoes among the ramekins and smooth the tops with the back of a spoon. Sprinkle with the remaining cheese.
  • Can be made in advance to this point and refrigerated until ready to bake.
  • To bake the gratins, preheat the oven to 350°. Place the gratins on a baking sheet and bake for 15 minutes until warmed through then turn on the broiler and cook for an additional 2-3 minutes until lightly browned. Serve.


Calories: 257kcal | Carbohydrates: 23g | Protein: 11g | Fat: 12g | Saturated Fat: 7g | Cholesterol: 42mg | Sodium: 388mg | Potassium: 422mg | Fiber: 3g | Sugar: 5g | Vitamin A: 16475IU | Vitamin C: 2.7mg | Calcium: 379mg | Iron: 0.8mg

Don’t Forget To “Pin It” For Later!

Looking for an alternative recipe for sweet potato casserole? Twice-Baked Sweet Potato Gratin is a delicious side dish w/ gruyere cheese. No marshmallows!

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  1. Linda Brewster says:

    Plan to make this but the recipe says it serves 6 and the # of ramekins filled as per the instructions is 4. Which is it?

    1. Sorry about that — I did fix it in the recipe. It makes 6.

  2. Sounds great. Wish I could email it to myself since can’t print from phone. Could send to friend too. I get the icon to d o so but doesn’t work.

  3. I found that over an hour at 375 was not long enough to cook the sweet potato. Any idea why?

    1. It could be the size of your sweet potatoes… You can increase the temperature to 400° for 45 minutes to an hour, but cooking is a tactile experience… I generally “test” the doneness by sticking the potatoes with a knife. If it inserts and exits easily, its done.

  4. Have you baked this in a casserole dish? If so how long does it bake

    1. I bake them in individual ramekins, but you could put them in a casserole. I’d let them cook for 25-30 minutes or until golden and bubbly.

  5. 5 stars
    Anything it’s Potatoes gets a big thumbs up from me. This looks so comforting and perfect for autumn.

  6. I’ve never seen a gratin done in this way or with sweet potatoes… i am loving the sound of your recipe!! I definitely need to give this one a try! Thanks!

  7. 5 stars
    This looks like the perfect addition to my Thanksgiving table, can’t wait to try it!

  8. 5 stars
    I love sweet potatoes and could eat them all the time! This is an awesome recipe and I can’t wait to make it. I never thought of making it as an au gratin! Perfect!

  9. 5 stars
    Okay, I am SUPER intrigued now because I have always been the same about sweet potatoes! But now I’m thinking about savory ones and the flavors here and I think you might have just converted me!

    1. If there’s an “ick factor” to marshmallow topped sweet potatoes, this is the cure.

  10. Kerryanne Rummerfield says:

    Thank you so much for this fantastic recipe, your delicious sweet potatoes accompanied our dinner last night and was a huge hit with my entire family.

    1. Kerryanne, thank you so much for letting me know! I’m glad that you and your family enjoyed them! They are special!

  11. Hello! I hope you’re having a good week. Your sweet potato recipe looked so tasty (seriously tasty – it’s on my shortlist of things to make) that I?ve linked to it my latest post on BuzzFeed.

    1. Thanks for including me and I’m so glad you liked this recipe. I think anything with gruyere is good!