Sweet Potato Casserole, Gratin Style

Is is a casserole, or is it a gratin?

I can’t quite decide…

One thing I do know is that it’s HMMM HMMMM GOOD!

This has got to be one of the best sweet potato dishes that I’ve had in my entire life.


Now, I really have to thank Cathy, over at What Would Cathy Eat, for that one, because if it hadn’t been for her inviting me to take part in her Healthy Thanksgiving Challenge, it might never have occurred to me to create a special dish for Thanksgiving.

You see, I’ve never reallly celebrated Thanksgiving. In fact, I don’t think that very many French Canadians do. Needless to say I don’t know much about what constitutes a traditional Thanksgiving menu, so I had do a little bit of research.

One of the menu items that really caught my attention was the Sweet Potato Casserole.  I was really intrigued by the concept of a sweet, almost dessert-like, savory side dish. However, I thought I’d tone that sweetness down one notch by adding a generous dose of caramelized onions. I find they just go soooo well with sweet potatoes.

And, since I’m such a huge fan of gratin Dauphinois, but have pretty much put a permanent cross on it, I decided to make this casserole in a similar fashion, by alternating layers of thinly sliced potatoes and caramelized onions, which I then topped with a crunchy pecan crust.

Of course, no gratin would be complete without some sort of a cooking liquid, and this one was no exception. I thought it needed something that would infuse it with the very essence of Christmas, so I invited my good friends cinnamon and rosemary to join the party.

To be honest, when I put this baby in the oven, I didn’t have high expectations. I was half prepared for a major flop. But let me tell you, when I came back from the basement after it had been in the oven for a half hour and that delicious smell hit my nostrils , I knew I had succeeded at creating something good, something REALLY good!

I sooooo couldn’t wait to taste it, but first, I had to let it rest a bit an awful long time, and then, I had to take pictures!!! It must’ve been one of my toughest, longest photo shoots ever. I was so hungry and this dish, sitting inches away from my eyes and nostrils and tastebuds, looked and smelled so incredibly good. Yet, I couldn’t touch it. Had to resist.

But when I finally got to it. OH! I almost died. This is seriously good. It’s sweet, it’s savory, it’s creamy and crunchy, it tastes just like Christmas. I could’ve eaten the whole pan right there, standing next to the kitchen table, right under that spotlight…

And you know what? I think that, from now on, I’ll be celebrating Thanksgiving!

Just so I can have this lovely casserole again…

Sweet Potato Casserole, Gratin Style

Yield: Serves 6-8

NF based on 1 of 8 servings

Sweet Potato Casserole, Gratin Style


  • 4 large onions, sliced into thin half-moons
  • 2 large sweet potatoes, peeled and sliced very thinly (use of a mandolin is strongly recommended)
  • 1 tsp salt
  • ½ tsp black pepper
  • For the sauce
  • 1 cup water
  • 3 tbsp unpasteurized honey
  • 1 tbsp Dijon musard
  • 1 tbsp fresh rosemary, finely chopped
  • ½ tsp salt
  • ½ tsp black pepper
  • ½ tsp cinnamon
  • ¼ tsp nutmeg
  • 100g pecans, finely chopped
  • 1 tbsp unpasteurized honey


  1. Preheat the oven to 375F
  2. Heat a little bit of olive oil in a large skillet over medium heat. Add the onions, salt and pepper and cook until very soft and caramelized, about 20-25 minutes. Add a few tablespoons of water from time to time to help deglaze the pan and soften the onion. Always wait until the water has fully evaporated before adding more.
  3. Arrange one third of the sweet potatoes in a rectangular baking dish. Make sure the potatoes overlap by about half a slice.
  4. Top with half the caramelized onions and spread evenly. Repeat with another layer of sweet potatoes, then add the rest of the caramelized onions, followed a final layer of potatoes. It might be a good idea to keep your prettiest potato slices for the final layer.
  5. Sprinkle chopped pecans evenly over that final layer of potatoes. Set aside.
  6. In a small mixing bowl, or large measuring cup, add all the ingredients of the sauce and mix until well blended.
  7. Very delicately pour over your potato dish, being careful as to not disturb the pecans.
  8. Cover loosely with foil and bake in the oven for 40 minutes, then remove the foil and cook for an additional 15 minutes.
  9. Remove from the oven, drizzle a tablespoon of honey over the pecan crust and return to the oven for an additional 5 minutes.
  10. Remove from oven and allow to rest for 10-15 minutes before serving.

What Would Cathy Eat


  1. says

    I love how you’ve made this a savory dish, with a bit of the traditional Thanksgiving sweetness from the pecans and honey. Furthermore I love that it fits my dietary needs (no wheat, dairy, or sugar.) Sounds delicious!

  2. says

    This is just stunning! I adore sweet potatoes, so I know I’d love this (and I can easily swap agave for the honey). :) And your photos make it all the more appealing. . . just gorgeous.

  3. says

    I think you’re amazing…because I would NEVER EVER be able to resist food that smells, looks, and most likely tastes delicious! I’d just eat it…then say, “oops” with no photos.

    • says

      LOL! I have to admit that the thought crosses my mind, sometimes… but I’m too addicted to taking pictures. I have to admit though that there are times when the “one or two bites in” pictures come quicker than they should’ve… 😉

  4. says

    Don’t you hate it when you make something that smells really good but you can’t eat it right away because you have to photograph it for the blog! Only fellow bloggers and husbands/wives of bloggers understand this plight! This looks really yummy and I love the combination of caramelized onions and sweet potatoes. yum!

    • says

      Yeah! The worst is when you take pictures of something that’s at its best when it’s really hot, but by the time you finally get to it, it’s pretty much gone cold, and then you think of how good it must’ve been when it was nice and hot! 😉 But nothing would ever stop me from taking pictures of my food, though. I don’t know, there’s just something about looking at your food through the lens of a camera. Makes it look a million times better. Or maybe it’s all the waiting that does it… 😉

  5. Mai says

    Oh gosh that looks like an amazing combination! How soft do the potatoes cook up? My sister just had dental work done and can’t have solid food for two weeks so I’m trying to find some recipes that’ll work for her (and the rest of us!) Although I suppose I could just toss a portion in the food processor and it’ll taste delicious anyway.

    • says

      Thanks Mai! The potatoes become really soft and creamy, so it wouldn’t be a problem for your sister to eat. She should, however, stay away from that pecan crust! So just remove the top layer for her and she should be fine! :)

    • says

      Oh, I LOVE honey and Dijon. They are such a great combination, and like you say, they add so much flavor! If you do end up trying this recipe, make sure you let me know how you liked it! 😀
      Oh, and I got your email, btw, and I thank you very much for it. I don’t mean to ignore you, it’s just that I am extremely bad with managing / answering emails… But I will get to it soon, promise! :)

  6. says

    You can definitely sneak out little bites. I do it all the time and then cover them up. :) How long does it take you to get so many perfect photos? I spent hours today just getting two okay ones. Sweet potatoes aren’t my thing but this looks lovely!

    • says

      I don’t know how you pull it off, Erin, I’ve tried a few times and it didn’t really work for me. I think I prefer to wait, then I can really dig in with all my heart! It doesn’t take that long, really. I usually prep my set as I cook, so I don’t know, maybe 15-20 minutes? Then, I have to clean the kitchen, and of course, that’s a whole ‘nother story! 😉

  7. says

    THIS IS GORGEOUS! I love love love sweet potatoes and you can’t ever go wrong with the addition of pecans, honey, warm spices and dijon!!! This dish would be a perfect addition to our Christmas meal! :) Thanks for sharing Sonia, just beautiful!

  8. Kinga says

    Great recipe, thanks for this perfect answer to my question staring at my fridge’s content the other evening. Unfortunately it didn’t turn out as on your photos, so I will give it another try soon and will make sure to properly measure the honey, which I did not do and so I ended up with overly sweet potatoes, but I could still tell that if done properly the dish will be amazing, so that is for next week! Thank you!

  9. Emily says

    How would this turn out if I made it a day ahead? We’re fighting for oven space for Thanksgiving and I’m weighing which recipes can be done in advance.

  10. says

    Quick question..planning on giving this a go this weekend…do the slices of sweet potato need to be any particular size or where your a mixture of shapes and sizes??? Want to make sure I get it right, had two failed butternut squash casserole attempts the weekend just gone! :(

    • says

      Oh no, making them all the same size would be way too complicated. They were the same thickness, but the ends of the potatoes are much smaller than the fat middle, so of course, you end up with smaller and larger slices. Just try and arrange them as best as you can, and of course, keep the best slices for your top layer!

      Can’t wait to get your feedback on that one!

      And real sorry to hear about your squash casseroles… what happened?

  11. Yui says

    I bet you have such a great skill to put art into your food. Just look how beautiful you create this dish. This looks so mouth-watering. I must have it in my birthday. Well, it’s tomorrow :)

    • says

      Thanks a bunch, Yui! That is so very kind of you to say! Hope you like the dish. Like you, I can’t get enough sweet potatoes! LOVE ‘EM! And I have to admit that this casserole was one of my favorite ways to enjoy sweet potatoes ever. Real worthy of a birthday meal. By the way, Happy Birthday to you! 😀


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