Sweet Potato Parmesan Gratin

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Cast-iron skillet of our delicious Sweet Potato Parmesan Gratin recipe

I write this post on a full belly, the best kind of belly if you ask me. I dined on leftover pancakes and a chocolate breakfast shake and it’s approximately 11:45 a.m. The fact is, when you work at home some days you don’t wake up until 8:30 and you don’t shower until 10, which means you don’t have coffee ’til 11 and simply are not hungry for breakfast until noon. But if you ask me, what’s the big deal? My belly got fed either way…

Sliced sweet potatoes and gold potatoes on a cutting board for making Sweet Potato Parmesan Gratin
Shredded cheese with sliced potatoes for making a delicious vegetarian sweet potato recipe

Speaking of full bellies, this sweet potato gratin gave me a full belly. Sliced sweet potatoes with one wee little yellow potato in the mix, sprinkled with a touch of thyme, lots of fresh grated Parmesan cheese and baked to perfection – this is the breakfast, brunch, lunch, snack of champions.

Pan of delicious Sweet Potato Parmesan Gratin sprinkled with fresh parsley
Pan of our Sweet Potato Parmesan Gratin recipe with a slice removed

I love how simple this dish is to throw together. It’s rustic in nature: loosely sliced sweet potatoes, a touch of salt, pepper and thyme, fresh grated cheese and a splash of milk. Throw her in the oven for an hour or so and you have a stunning and tasty dish on your hands. I personally prefer mine as an addition to lunch, but it also would be perfect alongside eggs or fruit for breakfast or as an afternoon snack.

The best part? It’s good hot, warm and room temperature meaning it’s a no-fuss kind of meal. If you haven’t guessed by now, that’s my kind of meal.

Batch of our Sweet Potato Parmesan Gratin recipe in a cast-iron skillet
Batch of Sweet Potato Parmesan Gratin with a slice removed from the pan

Sweet Potato Parmesan Gratin

A simple gratin featuring sweet potatoes, thyme, low-fat milk, and parmesan cheese. Healthier than your average gratin yet just as satisfying.
Author Minimalist Baker
Skillet of Sweet Potato Parmesan Gratin with a slice removed
4.46 from 11 votes
Prep Time 10 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 25 minutes
Servings 6
Course Side
Cuisine Gluten-Free, Vegetarian
Freezer Friendly No
Does it keep? 2-3 Days


  • 2 organic sweet potatoes (sliced in thin rounds)
  • 1 small red or yellow potato
  • ~1/4 tsp each salt and freshly ground pepper
  • 1 tsp thyme (roughly chopped // fresh or dried)
  • 3/4-1 cup Parmesan cheese (finely grated*)
  • 2 cups low-fat milk (I used 2%)*


  • Preheat the oven to 400 degrees F (204 C).
  • Butter or lightly oil a baking dish or cast iron skillet.
  • Place the sliced potatoes in a bowl and season generously with salt and pepper. Add the thyme and half of the cheese and toss together.
  • Transfer to the dish and pour on the milk. It should just cover the potatoes.
  • Bake 30 minutes, remove from oven and carefully drain off a bit of the liquid (about 1/3 cup as original recipe is written). Sprinkle the remaining cheese over the top and return to the oven.
  • Bake another 45-50 minutes, until the milk is absorbed, the potatoes are soft and the top and edges are golden. (Optional: drain off a bit more of the liquid as using low-fat milk instead cream can result in a bit of wateriness.)
  • Let rest at least 20 minutes before serving so the juices can redistribute.
  • Can be made ahead of time and reheated in the microwave or oven for serving.


*You can substitute other cheeses besides parmesan, such as gouda or asiago.
*You can use cream or half and half instead of low-fat milk, but it will add a lot more fat and calories overall.
*Nutrition information is a rough estimate.

Nutrition (1 of 6 servings)

Serving: 1 g Calories: 200 Carbohydrates: 27 g Protein: 11 g Fat: 5 g Saturated Fat: 3 g Fiber: 3 g Sugar: 6 g

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My Rating:

  1. Carla D says

    Sooo easy!! And my husband said WOW. (Hard to get a compliment) We did substitute rosemary and sage, and used cornstarch as a thickener, still required a draining of liquid, but used that to baste the top layer so it didn’t dry it out based on Janine’s note. So amazing, pretty sure hubby will request again. And i’ll be happy to oblige :)!

  2. Say WHAT says

    Made it today. Used two sweet and two regular potatoes. Also added Gruyere on top. Other than that, I followed the recipe. Very tasty and I have already saved this to my Pinterest recipe page. Thanks so much.

  3. Janine says

    My daughter and I made this last night and it was amazing. Based on other reviews about the liquid and need for thickening, we whisked in 1/4 cup of potato starch into the milk before pouring over the potatoes. Later, when the recipe instructions said to pour off the liquid, we saved it and poured it back over the potatoes so the top didn’t dry out. They came out moist with a crispy top and not too much liquid. This recipe is a keeper and so easy to make. Thank you fir sharing.

    • Avatar for Dana @ Minimalist BakerSupport @ Minimalist Baker says

      Thanks so much for the lovely review and for sharing your modifications, Janine. We are so glad you enjoyed it! Next time, would you mind leaving a rating with your review? It’s super helpful for us and other readers. Thanks so much! Xo

  4. Shawn Finley says

    Ok, well I’m a little let down on this recipe. It works but needs a thicking agent just a little and it would be 5 stars. Some thicking agent besides cornstarch or flour. In addition I would use fresh thyme over dried.
    But hey in the end it was a warm meal and satisfied.
    Single Dad.

    • Avatar for Dana @ Minimalist BakerDana @ Minimalist Baker says

      Thanks for sharing, Shawn! We’ll definitely revisit this one for improvements. A thickening agent would definitely make it more saucy.

      • JANINE says

        Especially for potato dishes, if you want to thicken things up, consider potato starch! My former husband (from Sweden) used it in sauces and I learned that it’s wonderful to add to soups, without that ‘too much flour’ taste. IKEA sells it but luckily, it’s also sold in the bulk foods section at my local grocery store.

  5. Elena says

    I love this Sweet Potato Gratin. I added lots of garlic and used 2 cups full milk and did not remove any liquid during baking, just baked it for a bit longer than an hour and added the rest of the cheese in between like it says in the recipe. It was perfect, still a bit moist and not dry at all. A new favorite! Thanks Donna. <3

    • Avatar for Dana @ Minimalist BakerSupport @ Minimalist Baker says

      Hi Caroline! We have not tried freezing it, but probably wouldn’t recommend it. if you give it a try, let us know how it goes though!

  6. leeegee says

    Finally splurged on a food processor and it took seconds to evenly slice the giant sweet potato for this dish. Waiting for it to cool, but it looks pretty good. Used whole milk because that’s what I had at the time, and I am out of white potatoes.

  7. Rick G. says

    Can’t wait to try this for Thanskgiving this year! Wondering what it would be like if I added a little cinnamon, brown sugar, vanilla, and bourbon to the cream?

  8. Courtney says

    This gratin looks divine, I may or may not have found it while perusing Pinterest for something creative to make for Christmas Eve dinner but no shame here! I think I’ll end up using all sweet potatoes because that’s what I have on hand (and prefer), but I’m wondering the difference of taste between using milk and half-and-half (or a mix of both).

    Have you tried it both ways, or what did you use? I prefer to keep it as healthy as possible, but sometimes cream just adds that necessary, er, creaminess.

    • Avatar for Dana @ Minimalist BakerDana @ Minimalist Baker says

      I’m sure half and half would make it even more decadent. But I’d agree, a mix of both would be best. Good luck!

  9. Mavis Jones says

    I made this but used your Vegan Parmesan Cheese in place of the Parmesan Cheese and used Flax Milk in place of the 2% milk. Came out yummy. I will definitely be making this again.

  10. Erika Kubick says

    Beautiful, fast, easy recipe! I’m writing a post about cooking with whole foods on my blog, and I’d like to share this with full credit. Please let me know if that’s alright with you! Thanks!

  11. VegasBee says

    Have you made a vegan version of this and was it good?? Wondering if I can sub almond milk and your recipe for vegan parm?

  12. Katy says

    This recipe looks perfect for a family gathering tomorrow. I work full-time. Can I bake it partially today and then tomorrow at the dinner?

  13. Norm Dunkin says

    Made this dish today for dinner. I have been experimenting with sweet potatoes lately so I decided to give this a try. I have also been trying Parmesan recipes. The combination of sweet potatoes and Parmesan was really good. Can’t wait to have the leftovers for breakfast. This recipe is a keeper. I can see this as a dish for any meal of the day.

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  15. Jason says

    Very nice. I had one orange sweet potato and one purple sweet potato on hand. Between the milk and the purple sweet potato, the result looked like pepto bismol surprise but tasted good.

  16. Mirandamom says

    Substituted fresh sage for the thyme. The dish was very good but the herbs got lost. If I do it again with sage I’ll double the amount. But I’m thinking next time, rosemary!

  17. Laura says

    This sounds so delicious and easy to make. I hope that I get to try it soon – I may have to re think my meal plans!

  18. Bogna says

    Love it! Simplicity is the best! My friends really enjoyed it! (I’ve got very good feedback!) Question: Could you recommend a good substitute for milk? I’m vegan and try to figure out what the substitute would work for vegan version of this awesome gratin.

  19. Laura says

    What’s your trick for slicing them so thin? I have the hardest time slicing sweet potatoes into chunks for mashed, I can’t imagine getting them that thin. Did you use a vegetable slicer? Have you ever tried to use one with the sweet potatoes?

    • Avatar for Dana @ Minimalist BakerDana @ Minimalist Baker says

      Nope! I just use a really sharp knife and slice them uniformly thin. Practice makes perfect! Otherwise, get a mandolin – I hear they slice really well.

      • SkippyMom says

        I do exactly the same. I always sharpen my good knife on the bottom of a ceramic coffee mug [try it, it works SO well] as a sharp knife is incredibly important. Uniform size is the key, not so much as the thickness because you want them to cook at the same rate.

        But as you said = practice makes perfect. :) Love the recipe and I have two sweet potatoes and leftover ham just asking to be made into a new dinner. Thanks so much.

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  21. Amy says

    Brilliant recipe! So yummy, I’m sitting here typing this with a full belly thanks to this recipe. Excited to try more of your recipes!

  22. Sam says

    Is there a functional reason for using a single white potato in the mix? I was wondering if the recipe would still work with all sweet potatoes?

  23. Janani says

    So I’m making this tomorrow for Thanksgiving dinner! I wonder how Gruyere cheese will taste with this dish… hmm.. But, for the sake of pleasing everyone- I shall stick to parmesan and asiago!

  24. De says

    YUM! I’ve realized I’m obsessed with sweet potatoes so this is perfect for me. I love to use my cast iron skillet too :) Thank you!