Sweet potatoes are seriously the best.
Though they’re not technically in the same family, a sweet potato can do almost anything a regular potato can, and can probably do it better. They can be french fried, mashed, baked, roasted, you name it. You can even turn these puppies into dessert! Take that, potatoes!
Sweet potatoes have more flavor and are (obviously) sweeter, but what you might not consider is that they’re also packed with beta-carotene and calcium, and have almost 300% of the vitamin A you need in a day. Now that’s what I call a superfood.
One thing I’m not crazy about when it comes to sweet potatoes though, is the tendency to make them even sweeter while serving them with dinner. I mean, if you want to make a dessert, go ahead and make a dessert. There’s nothing better than a good sweet potato pie. But if you’re serving sweet potatoes as a side dish I really don’t get the desire to cover them in marshmallows. I guess its just not for me. You wouldn’t cover a radish or a green bean in brown sugar and marshmallows would you? Well, I don’t know, maybe you would. I wouldn’t though!
I know some people really dig candied sweet potatoes at Thanksgiving, but it’s just not for me. Sorry.
Anyway, because I’m a lunatic forward-thinker, I’m already planning my Thanksgiving menu. You already know this, but I take this holiday pretty seriously. I really want to highlight sweet potatoes on my table this year, but I’ll be damned if a marshmallow comes anywhere near my little orange beauties. I love mashing them just like potatoes, with lots of butter, but this year I want to do something special.
It didn’t take me long to decide on some type of layered casserole. A gratin is the perfect solution. Rich and satisfying, with a touch of cream and cheese to gussy things up.
Most gratin recipes call for a salty hard cheese like parmesan, but I thought the sweet potatoes called for something a bit creamier and nuttier, so I opted for Jarlsberg. If you’re not familiar, Jarlsberg is a mild cow’s milk cheese from Norway. It has large holes like swiss, but it’s more buttery and nutty. If you can’t find it I think Gruyere would work really well too.
I wanted to pack as much savory flavor into this gratin as possible, so I poked around the internet until I found a recipe that sandwiched a layer of caramelized onions between the sliced sweet potatoes. Yes please. To take the flavor even further I went and added a few thing; some thyme and parsley along with the sage in the original recipe, as well as a bit of dijon mustard, some ground cayenne pepper for kick, and some smoked paprika for a nice hint of smoky depth.
This is not only the perfect side dish for Thanksgiving, but really any large gathering or dinner party. On top of being crazy delicious, I think it’ll travel really well too, and could easily be prepared ahead and reheated.
As soon as I took my first bite, I knew I’d reached sweet potato perfection.
If you want to know how good it tastes, let me just say this. Russell is spoiled by my cooking. While he absolutely loves and appreciates everything I make, most of my cooking gets little more than a “thank you” or “yummy”. This though, he couldn’t shut up about. He went on and on about how delicious and perfect it was. He ran out of words. And frankly, I don’t think there are enough words in the English language to properly describe this gratin. A few that come to mind though are creamy, savory, spicy, smoky, cheesy, buttery, tender, rich, delicious, satisfying, hearty, flavorful, heavenly and amazing… Oh yeah, and Bow-chicka-wow-wow.
Sweet Potato Gratin
2 tablespoons unsalted butter (plus more for pan)
2 medium onions, sliced into thin half circles
3 pounds sweet potatoes or yams (3 to 4 large)
Kosher salt and fresh ground pepper
2 tablespoons fresh sage leaves, finely chopped
1 tablespoon fresh parsley, finely chopped
1 teaspoon fresh thyme leaves
1 teaspoon dijon mustard
1/2 teaspoon smoked paprika
1/4 teaspoon cayenne pepper powder (optional)
1 1/4 cups heavy cream
Topping:
2 tablespoons unsalted butter
3/4 cup panko breadcrumbs (or plain, unseasoned bread crumbs)
3/4 cup grated Jarlsberg cheese (or Gruyere)
3 tablespoons fresh parsley, finesly chopped
Heat the oven to 350°F and butter a 9×13 casserole or gratin dish. In a heavy skillet heat 2 tablespoons of butter to a foam and add the sliced onions. Season them with a bit of salt and slowly caramelize them over medium-low heat, stirring frequently. To get them nice and brown (but not burned) should take about 20 or 30 minutes.
While the onions sizzle away, peel your sweet potatoes and slice them into 1/4-inch thick disks. Getting thin and even slices will be easiest with a mandolin, but is totally possible with a sharp knife and a steady hand. Layer half of the slices in the buttered dish, overlapping them in tight rows or spirals. Season the layer with salt and pepper.
Once the onions are soft and caramelized to your liking, add the sage, parsley, thyme, dijon mustard, paprika, cayenne pepper, and cream. Bring to a simmer, stir well, and cook until the cream is thick and bubbly, about 2 minutes. Remove from the heat.
Do your best to remove the onions from the cream with a slotted spoon. Spread the onions evenly over the first layer of sweet potatoes. Layer the remaining sweet potatoes on top, in the same rows or spirals as before. Season with kosher salt and black pepper, and evenly pour or spread the cream over the top. The cream will not cover the potatoes completely or fill the dish and you will think there’s isn’t enough. Don’t add more! Too much will make the sweet potatoes mushy.
Cover the dish with foil and bake for 15 minutes. Remove the foil and bake for 10 or 15 minutes more, or until the potatoes are just tender. (Note: If your sweet potato slices are thicker than 1/4 inch- baking time is likely going to take longer.)
While the sweet potatoes are in the oven, melt 2 tablespoons of butter and let cool a bit. In a small bowl, pour the butter over the bread crumbs, grated Jarlsberg and chopped parsley, and toss well to combine. Sprinkle evenly over the top of the gratin and return to the oven (uncovered) for about 15 minutes or until brown and crispy. Let cool for at least 15 minutes before serving.
Brooklyn Homemaker 
Interesting… Being from the south, I’ve always had them sweetened. I don’t care for them candied or with marshmallows. I do like them prepared as a casserole w/ butter, pecans, brown sugar and cinnamon. David says they taste like sweet dirt! WTH?!? I have pinned this recipe to try, perhaps he would like them prepared this way… Do you think cutting this recipe in half would effect the outcome?
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Hahaha! Sweet dirt! Too funny! I think that as long as you make it in a smaller dish so there are still two layers of potatoes it should be fine. Maybe try it in an 8×8 pan or something like that? I hope you and David love it!
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Thanks, Tux! Was just trying to figure out a way to not have so much in case it still tastes like sweet dirt to him… ;)
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I’ve definitely already started planning our Thanksgiving menu. So you’re not alone there ;-)
Sweet potatoes trump white potatoes for me every time. I just love them. I don’t care for the marshmallow casseroles either, to me they’re enough to stand on their own two feet.
Great job, this looks like an amazing side dish to have for Thanksgiving :-)
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I’m so glad I’m not alone! I was afraid to talk smack about marshmallows on sweet potatoes for fear of offending people- but I think a lot of people feel the same way as me- and maybe even think they don’t like sweet potatoes because of the “candied” affect.
I wish we could spend thanksgiving together! I hope you have a great one!
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We never buy white potatoes anymore. We just love sweet potatoes. Usually with jus a little olive oil and S&P. This looks amazing, and a wonderful side dish for the holidays.
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Thank you- and I’m right there with you- I especially love mashed sweet potatoes with butter and S&P
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I do come from a family of candied sweet potatoes but I understand your hesitation about marshmallows, Tux. (I usually scrape the marshmallow part off.) My favorite way to eat sweet potatoes is roasted whole with butter stuffed inside when they are done. I love that crusty top on your casserole though! Must give your cheesy sweet potato version a try!
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Truth be told Stacy, so do I! They’ve always been a staple at Thanksgiving but I’ve usually passed them up because the marshmallows just took the sweet and savory thing a little too far for me. When I was a kid I did like them, but now I even like my desserts with a more subtle sweetness.
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hmmmm!
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;)
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Sweet potatoes are a favourite of mine – they also have lower carbohydrates than white potatoes. Any anything mixed with caramelized onions is a winner in my books!
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I know! Sweet potatoes AND caramelized onions? And healthy(ish) too??? What could be better!
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what a great year round recipe as far as I am concerned. Rich and favorable and certainly makes a color splash in any meal.
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I definitely think these flavors will work any time of year- and the fact that this will transport easily makes it perfect to bring to a dinner party or potluck to impress your friends and family! YUM!
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never thought to make a sweet potato gratin. what a great idea!
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Thanks! I’ve never made one before either, but now that I have I think it’s going to be a new Thanksgiving staple!
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Oh my gosh, where was this at Thanksgiving? Buried in the blogosphere, damnit! Man this looks super delicious. Everything about this is a major home run!
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There’s always next year!!!
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If I make this the night before and refrigerate, how should I reheat it so it’s not mushy? Should I wait to add breadcrumbs until I reheat?
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Hi Lauren!
I’m so sorry it took me a few days to get back to you. I’ve been on vacation and just got back.
So, sweet potatoes will tend to get a bit softer than regular potatoes when cooked through, but straight from the oven or reheated they may be a touch “mushy” but not in a way that isn’t appealing.
My advice would be to cook the casserole completely to make sure the sweet potatoes are completely cooked through the first time, or they may not finish cooking correctly when you go to reheat them.
I would definitely wait to add the bread crumbs until you’re re-heating it for serving though. That way they’ll be crisp and offer a nice variation in textures.
I hope that helps!
Thanks for commenting!
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Wow, I was searching the internet for something I could make with my jaresberg cheese and I came across this recipe. It used so many ingredients that I had on hand that I wanted to use up that I had to go for it – fresh sage and thyme, sweet potatoes, etc. This was hands-down the best dish I have ever made. My husband said it was like we were eating at a nice restaurant, he also loved this dish! This is definitely going in our rotation of regular dishes. And now that I’ve discovered your site and how delicious this recipe was, I’m totally going to make more from your recipe archives, I’m so excited that I’ve found your blog! Thank you! PS – I live in Brooklyn too, off the Lorimer L stop :)
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Thank you so much for your sweet comment Elyse! I’m so happy that you loved this dish and that you had so many of the ingredients on hand! I love hearing from people who have tried my recipes (especially when they’re happy with the results!)
Let me know what recipe you try next!
Maybe we’ll run into each other one of these days- I’m off the L train too, in Bushwick.
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