Sweet Potato Gratin

I wrote a post a couple of years ago when I started this blog, called “Please – No Marshmallows!” Of course, I was referring to the rampant use of marshmallows on sweet potatoes in the U.S. Now, if you love this combination – great! What I have to say will not deter you. But I’ve just never understood putting something so sweet on something sweet. I mean, for god’s sake, they’re called sweet potatoes for a reason!

I remember the first time I had sweet potatoes with marshmallows. It was my second year of college and I wasn’t able to fly home just for Thanksgiving, so I went with a roommate to her parents’ home in Los Angeles. I was so excited about having a “normal” Thanksgiving meal because I’d always been so deprived of traditional dishes.

My mother was a chef in her own right. She’s French, and I think all French people must be fabulous cooks. We never knew how spoiled we were with her cooking. She only used fresh ingredients, and I don’t remember her ever opening a can. We certainly never ever ate fast food.

Being French, however, and the fact that she always disliked turkey, which I think a lot of French people do, she never embraced the U.S. Thanksgiving holiday. The last Thanksgiving meal I had at her home was duck a l’orange. Okay, it’s good. But I yearned for turkey and stuffing and sweet potatoes with those darn marshmallows.

So then I got my chance, in 1974. My friend’s family was very sweet and embraced me like one of their own. In fact, there was no yelling or throwing of pots, which was something else I wasn’t used to.

Then came dinner. Oh my. I guess my taste buds were quite sophisticated at my young age, and hopefully I didn’t show my reaction to the various dishes, but I was horrified. The turkey was dry, the stuffing was stove-top, which is a very popular American boxed brand, and the sweet potatoes were smothered in melted marshmallows. To make things even worse, the pumpkin pie was purchased and came in a litle foil pan. And then cool whip… I can’t go on.

Sweet potatoes are a fabulous vegetable, and to me, they shine with the addition of garlic. And butter and cream. And cheese. They’re also fabulous mashed, but today I’m making them into a gratin. And I’m using Reblochon, one of my favorite stinky cow cheeses.


There are so many ways to make a potato gratin from scratch, but I’m par-boiling the sweet potato slices in order to speed up the baking process. It’s an extra step, but sometimes it seems like it takes forever for sliced potatoes to bake in cream. And you end up with dish of milky, uncooked potatoes. So I’m just helping their cooking along, and that way less cream is required as well. So here’s what I did.

Sweet Potato and Reblochon Gratin

4 medium-sized sweet potatoes
2 ounces butter
4-5 cloves garlic, minced
3/4 cup 1/2 & 1/2 or heavy cream
16 ounces Reblochon, or Gruyere, or Fontina

Preheat the oven to 375 degrees Fahrenheit.


Peel the potatoes and slice them using a mandoline or a food processor.


Bring pasta pot filled with salted water to a boil on the stove over high heat.

Add the sweet potatoes and cook them for 5 minutes. The cooking time will depend on how thinly you sliced them. Mine are approximately 1/8″ thick.


Remove the potatoes and let them drain in the sink. I prefer to use a pasta pot with the insert, so the slices don’t break apart when they’re poured into a colander. Let them cool.


In a small pot, melt the butter and add the garlic. Stir for just a few seconds, then pour in the cream.

Reduce the mixture to approximately 1/3 cup.

Slice the cheese however way you can. I kept the cheese chilled to facilitate slicing, but soft cheeses are always a little more challenging.


Using an appropriately sized oven-proof baking dish, well buttered, place one layer of sweet potatoes into the dish. Add cheese, then continue, alternating sweet potatoes and cheese.

Make sure to season the sweet potatoes with salt and pepper.


Then carefully pour the cream mixture over the top.

Bake until the cheese has melted and is golden brown, approximately 25 minutes.


Let the gratin cool slightly and set. It’s easier to slice that way.


Because of the Reblochon in this gratin, it takes a pretty strong protein like a filet mignon or lamb chop to pair well with this gratin. Tomorrow I’m serving it with ham.


It will also keep well in the refrigerator, and can be heated in the oven or microwave.


So try sweet potatoes once without the marshmallows. Only that way you can truly taste their sweet goodness.


By Published On: January 5th, 201543 Comments on Sweet Potato Gratin

About the Author: Chef Mimi

As a self-taught home cook, with many years in the culinary profession, I am passionate about all things food-related. Especially eating!


  1. Linda Duffin January 5, 2015 at 8:13 AM - Reply

    As an unwitting Brit, I read your post with my hand over my mouth. No! Good grief! Do they really do that? I mean us Brits have committed a fair few food sins over the years but marshmallows on sweet potatoes? Your version, however, sounds delicious. Garlic. Cream. Reblochon. What’s not to like? Gorgeous.

    • chef mimi January 5, 2015 at 11:19 AM - Reply

      Yes, they really do do that. And they’re proud of it. I’ll probably get a few defensive comments!

      • Linda Duffin January 5, 2015 at 11:20 AM

        Still got my hand clamped over my mouth ….

  2. sallybr January 5, 2015 at 8:54 AM - Reply

    Never understood marshmallows, and not only on sweet potatoes, but on their own. To me it is the definition of sugar overkill, and just looking at them I feel a little queasy.

    even those smores by the fire never really conquered my heart – I might grab one due to peer pressure, but dislike the mess and the sugary taste ;-)

    fun killer? who, moi?

    • chef mimi January 5, 2015 at 11:20 AM - Reply

      Of course, you’re not American. Do you remember the first time you ate them?

      • sallybr January 6, 2015 at 11:19 AM

        Oh, gosh… I think it was by the fire on a lake with Phil and the kids. I was shocked by the stickiness of it, and how sweet it was, and could hardly wait to wash my hands.. But I put on a brave face and endured the whole thing as if I was born with a marshmallow in my hand ;-)

      • chef mimi January 7, 2015 at 9:44 AM

        see… you never forget!

  3. Elaine @ foodbod January 5, 2015 at 9:43 AM - Reply

    Sweet potato and marshmallows??? Really?? Sounds horrible :(
    Your dish however looks gorgeous :)

  4. DellaCucinaPovera January 5, 2015 at 9:43 AM - Reply

    I’m right there with you Mimi. Sugar on top of cake… I can’t stand marshmallows on sweet potatoes (or any tuna, green bean casserole, to boot). But mountains of this.

  5. nowathome January 5, 2015 at 10:30 AM - Reply

    I like the way you’ve done it! Will give it a try!

  6. chef mimi January 5, 2015 at 11:17 AM - Reply

    Oh yeah! I remember that! I love the touch of garlic and cream!

  7. chef mimi January 5, 2015 at 11:18 AM - Reply

    They’re both so delicious, aren’t they?!!!

  8. chef mimi January 5, 2015 at 11:21 AM - Reply

    Oh, thank you! I’m going through my comments and waiting for the first one that’s defensive of that traditional combo. I really don’t care, as long as people don’t make me eat them!

  9. dianeskitchentable January 5, 2015 at 1:03 PM - Reply

    I have to laugh because I can’t stand marshmallows on top of sweet potatoes however…I make a sweet potato casserole with a brown sugar crumble topping. Yes, it’s sweet but it seems to be the first thing to disappear on Thanksgiving. Maybe it’s because it’s like having desert first. That said, I can easily see myself enjoying this.

    • chef mimi January 5, 2015 at 4:51 PM - Reply

      I believe it. Most people love sweet things!

  10. Julie is HostessAtHeart January 5, 2015 at 3:23 PM - Reply

    We actually prefer sweet potatoes to white now. Usually with just a little olive oil, s&p and rosemary. We do dress them up once in a while with some pecan. I’ve never thought about preparing them as a gratin. Amazing.

    • chef mimi January 6, 2015 at 9:40 AM - Reply

      They’re lovely in a gratin. You don’t really need the cheese. I was just in a cheesy mood!

  11. Charlotte January 5, 2015 at 4:20 PM - Reply

    The first time I saw sweet potatoes with marshmallows was when I went to live in Boston. I had never had a sweet potato in my life so I assumed sweet potato gratin was a dessert. Because of the marshmallows, right? It was not my best experience – but certainly one I remember! Reblochon sounds much MUCH better as a topping

    • chef mimi January 5, 2015 at 4:49 PM - Reply

      Yeah, I had that same kind of experience, And with this recipe, cheese is really necessary – just some butter and garlic!

  12. chef mimi January 5, 2015 at 4:48 PM - Reply

    Gross, huh?!

  13. chef mimi January 5, 2015 at 4:50 PM - Reply

    I understand, but she could have cooked a turkey once every year…

  14. gwynnem January 5, 2015 at 5:28 PM - Reply

    I’ve made two sweet potato gratin recipes that were bland. This one looks great. Just pinned it to a Pinterest recipe board!

  15. Kitsch n flavours January 5, 2015 at 6:01 PM - Reply

    Ah, white balance – with digital photos it’s so necessary to edit a little. Or maybe you tweak camera settings.
    Would’ve loved to have seen your face back then, at the Thanksgiving meal! The only one I’ve been to was in Houston, several years ago. The food was nice. It just wasn’t hot. Found slightly warm turkey to be so strange. Fun afternoon, though.
    Have never thought of using sweet potato in a gratin. Looks and sounds delicious.

    • chef mimi January 5, 2015 at 8:25 PM - Reply

      Warm food? Ugh. Well, it does take time to get everything out and ready for Thanksgiving. Maybe that was it? Sweet potatoes are wonderful in a gratin. Cheese isn’t even necessary!

  16. chef mimi January 5, 2015 at 8:17 PM - Reply

    out of a can? oh my. I’ve never heard of sweet pasta, but why?????!!!

  17. chefjulianna January 6, 2015 at 12:32 AM - Reply

    Wow! Now this is my idea of sweet potatoes!! I am with you on the marshmallow thing! Don’t get it either :/ Too funny about your 1974 Thanksgiving dinner – and so nice that we are evolving in NA! I am bookmarking your recipe, as I am always on the lookout for new and delicious ways to prepare one of my Fave vegetables! :D

  18. Marisa @missmarzipan.com January 6, 2015 at 5:40 AM - Reply

    Perfect gratin! And I recall sweet potato with marshmallows from a visit with my uncle in Texas! EEK!!!

  19. chef mimi January 8, 2015 at 8:22 AM - Reply


  20. chef mimi January 8, 2015 at 8:21 PM - Reply

    You know, this gratin would be greatly satisfying without cheese. But gruyere or fontina, or a good monterey jack would work well!

  21. chef mimi January 8, 2015 at 8:22 PM - Reply

    but I could argue that cake with icing is definitely in the dessert category!!! jello salad. I’ve had it once. oh my – that’s a whole other post!!!!!

  22. Lesley at Lola Rugula January 9, 2015 at 10:03 AM - Reply

    This looks wonderful – and I’m not even a huge fan of sweet potatoes. :)

  23. Choc Chip Uru January 10, 2015 at 1:49 PM - Reply

    Marshmallows? I feel like this is something out of a surreal foodie dream, but I trust your expertise when it comes to flavour combinations :D
    I love how tasty it looks though!

    Choc Chip Uru

  24. chef mimi January 14, 2015 at 7:51 AM - Reply

    Hahahaha! I know the feeling!

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