This sweet potato gratin has everything you need to make a crowd-pleasing dish: a garlicky herb cream sauce, gruyere and parmesan cheese, and thinly sliced sweet potatoes.
Sweet potatoes with marshmallows is a Thanksgiving staple but if you are in the mood to swap sweet for savory then this amazing sweet potato gratin with gruyère cheese from Melissa Clark & the NYTimes is just the recipe for you. I’ve made this slightly adapted version for holiday gatherings for the last couple of years and will continue this tradition in the foreseeable future. This sweet potato gratin has everything you need to make a crowd-pleasing dish: a garlicky herb cream sauce, gruyere and parmesan cheese, and thinly sliced sweet potatoes.
This recipe is not necessarily a “quick” or super “easy” dish. It takes time to simmer and reduce the herb cream sauce, to thinly slice the sweet potatoes with your mandoline (watch your fingers), to freshly grate the gruyere and parmesan, and to layer all the ingredients.
It is, however, one of those labor-of-love recipes that gets a big payoff in the end with huge flavor and compliments to the chef. If you are in need of a side for your next holiday dinner or potluck, this is it.
Savory Sweet Potato Gratin Recipe with Gruyere and Parmesan from NYTimes
This sweet potato gratin has everything you need to make a crowd-pleasing dish: a garlicky herb cream sauce, gruyere and parmesan cheese, and thinly sliced sweet potatoes.
Ingredients
- 3 tbsp butter for greasing pan
- 1/3 cup Parmesan plus more for sprinkling on top of gratin
- 2 cups heavy cream
- 2 tbsp fresh sage chopped
- 2 tbsp fresh rosemary finely chopped
- 4 large garlic cloves minced
- 1/4 teaspoon nutmeg original recipe recommends fresh nutmeg, although I used ground
- 1 1/2 teaspoons kosher salt plus more to taste
- 3 eggs, large lightly beaten
- 3 lbs sweet potatoes about 4 large.
- freshly ground pepper to taste
- 1 2/3 cups grated Gruyère cheese around 6 1/2 ounces
Instructions
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Prepare your sweet potatoes by rinsing and peeling.
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Slice your sweet potatoes into 1/8 inch rounds using a mandoline or a sharp knife. You can prepare the sweet potatoes ahead of time as this can be time consuming.
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Preheat the oven to 400 degree F and butter two pie dishes. Also butter foil for covering the pan later. Sprinkle parmesan over the bottom of your dish(es).
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Combine cream, sage, rosemary, garlic, nutmeg and a pinch of salt in a pan over medium heat. Whisk often until the garlicky cream sauce begins to simmer. Keep stirring for about 10 minutes, until the sauce thickens somewhat.
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In a large bowl crack the eggs and beat them just enough to break up the yolks. Slowly add the cream sauce to the eggs, whisking as you combine. Put your cream sauce, sweet potato slices, and the grated cheese near your baking dishes.
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Divide 1/3 of the sweet potatoes between the two pie dishes. In one dish assemble the sweet potato slices into a layer over the grated parmesan, each piece somewhat overlapping the last starting on the outside border and moving in towards the center of the dish. Repeat with second pie dish. Sprinkle both with salt and pepper to taste and divide 1/3 of the cream sauce between the two pie dishes. Top with 1/4 C Gruyere cheese on each pie dish.
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Repeat this step with another layer. Add 1/3 of the potatoes between the two dishes, sprinkle with salt and pepper, divide 1/3 of the cream sauce and sprinkle 1/4 C Gruyere cheese on each dish. For the final layer divide the remaining 1/3 of potatoes, salt and pepper, the rest of the egg mixture, but set the remainder of the Gruyere cheese (about 2/3 cup) to the side. Press down firmly with a spatula to compact the potato mixture. Cover with foil, place in oven and bake for 40 minutes, or until the potatoes are soft enough to easily pierce with a fork. Remove the foil, sprinkle on the rest of the Gruyere cheese and little Parmesan (if you have extra) and cook for an addition 25 to 30 minutes until bubbly and browning.
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Let cool for about ten minutes and then serve.
If you love sweet potatoes you should check out these recipes- Chicken sweet potato slow cooker tortilla soup & Sweet potato and ricotta pizza with sage.
If you make this sweet potato gratin recipe please share on instagram using hashtag #rainbowdelicious & and tag me at @rainbowdelicious , I’d love to see what you are up to in your kitchen!
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Not a real fan of sweet potatoes, but I love white sweet potatoes. Do you think they would taste okay as a substitution?
I imagine it would be fine!
Oh my goodness! This looks so good. And I LOVE Sweet potatoes. Definitely trying this for Thanksgiving!
Enjoy, Jessica!
I am a die hard when it comes to my sweet potatoes with marshmellows but this was such a nice change. I may just make it this year as another option for dinner.
Sometimes I do both- you can never have too many sweet potatoes in my opinion… more leftovers!
I was looking for a new sweet potato recipe for the holidays and tested this out for immediate fam this week. Everyone loved them! Will be making for the big day.
Aren’t they so good! Glad you and your fam liked them and hope they work out on Thanksgiving too!
That looks awesome, and I’m loving all the herbs and spices in this. And that gruyere cheese! Going to make this soon. 🙂
I hope you enjoy it Anita!
This looks so yum!! I’d love to try for a weeknight dinner.
I hope you enjoy Estee! It would go great with a roasted chicken for dinner!
We make something like this every year!! It is always devoured. Love the gruyere in it.
It is always a hit during the holidays in our family too! Thanks Erin!
I do love sweet potatoes! I’ve never had them in a gratin before but I will be changing that soon enough! Love the gruyere!
Sweet potatoes are so good in a gratin, I hope you get to try Beth!
Yep, I’m up for a fun change like this at my Thanksgiving dinner! Delish!
Enjoy Beth!
This seriously looks mouthwatering delicious! I’m going to try this out this weekend in preparation for Thanksgiving!
Hope you love it Sapana!
This looks amazing. Before I try it there seems to be a word missing in the last section. “Cover with foil for 40 minutes until potatoes are soft”. Does this mean cover and put in the oven?? Since it then says uncover and cook for additional period of time with the extra cheese. Thanks!
Hi Catherine, thanks for pointing out this error. I’ve changed the wording to reflect what was meant. Yes, cover and put in the oven for 40 minutes, or until sweet potatoes are soft. Enjoy the recipe, it is a family favorite at our house!