This Butternut Squash Gratin is made with leeks, sage, and walnuts. It is a delicious fall side dish, 100% worthy of the holiday table! Vegan-adaptable and gluten-free. Video.
Why You’ll Love This
Cozy flavor and texture: We can’t decide what we like best about this Butternut Squash Gratin- the melted leeks, the toasted walnuts, the fresh sage, or the hint of nutmeg that infuses the whole thing with goodness.
Ultimate comfort food: Think of this like scalloped potatoes, but made with butternut squash instead. Hearty and satisfying, this is pure and total comfort food.
Thanksgiving side or vegetarian dinner: I suppose one might categorize this as a Thanksgiving side dish and yes- that is what it was designed for, but truth be told, we’ve been eating this for “dinner” the last few nights, along with a salad and sourdough bread and couldn’t be happier. Use it as you please.
Make a large batch or cut the recipe in half: The recipe makes a big batch- enough to serve eight, so feel free to cut this in half for smaller gatherings.
Butternut Squash Gratin Ingredients
- Butternut squash: The large size of butternut lends this winter squash to round pieces that can easily be layered. You can sub other large types of winter squash, like sugar pumpkin, red kuri, or kabocha.
- Leeks and garlic cloves: Add savory, aromatic depth to the overall flavor of the dish.
- Sage leaves: For earthy, herby flavor that makes this dish even more cozy!
- Heavy cream: Or sub plant-based cream, milk, or coconut milk for a vegan variation.
- Nutmeg, onion powder, salt, and pepper: Mixed with the cream to create velvety, fragrant layers. Onion powder is optional.
- Gruyère cheese: Or sub parmesan or vegan parmesan.
- Toasted walnuts: Add a crunchy, toasty topping that pairs well with the creaminess of the dish. You could always try panko breadcrumbs instead.
Butternut Squash Gratin Instructions
Preheat oven to 375F.
Step one: Peel the butternut squash, scoop out the seeds, and slice into 1/8 inch thick rounds. Set aside 12-15 of the “prettiest” slices to be used for the top layer. You’ll have 3 layers of butternut, so you can divide them into 3 piles, reserving any misshapen pieces (like the half moons) for the middle.
Step two: Slice and rinse the leeks. No need to dry them- the moisture will help them soften. Heat oil or butter in a large skillet over medium heat. Sauté leeks 8-10 minutes, covering the pan halfway through to soften.
Add garlic, sage, and a pinch of salt, cooking 2-3 more minutes. Turn off the heat.
Step three: In a medium bowl, whisk together the cream, salt, pepper, nutmeg, and onion powder.
Step four: Grease a 9 x 13 inch baking dish or 11-12 inch round casserole dish. A big shallow pan is best for even cooking.
Add 1/4 cup water to the bottom of the pan, then add your bottom layer of butternut squash, overlapping slightly. Sprinkle with half of the leek mixture. Drizzle with 1/3 cup of the cream mixture. Add 1 ounce of gruyere (about 3-4 tablespoons grated).
Now add the second layer of butternut squash, scatter with remaining leeks, then drizzle with 1/3 cup cream mixture and more of the gruyere cheese.
Add the top layer of butternut, overlapping and pressing down so that it does not dome in the middle.
Pour the remaining cream over top and add a light sprinkle of cheese. Add the toasted walnuts. If you’d like, some freshly grated nutmeg is nice over top too!
Give the pan a gentle shake, press down the center again so it is level. Cover with parchment as the first barrier, then with foil. If the foil isn’t touching the food, then you can skip using parchment.
Step five: Bake 45 minutes, then carefully uncover the pan. Use the tip of a knife to see if the butternut is fork tender. Bake at 400 degrees F uncovered for 15 minutes until golden.
Step six: While the gratin is baking, heat 1-2 tablespoons of oil or melt butter in a pan over medium heat. Add 8 sage leaves, sautéing each side for 30 seconds or until crisp. It helps to try a tester first! Transfer to a paper towel for a couple of minutes. When the gratin is ready, arrange the sage over top. Add thyme sprigs or a little parmesan cheese if desired!
Chef’s Tips
- Slice the butternut squash as thinly as possible. Aim for 1/8 of an inch. The thinner the slices the faster this will cook.
- Use the prettiest butternut squash slices for the top layer. And separate them into 3 piles, with larger pieces for the bottom, misshapen pieces for the middle (like those half-moon pieces!), and pretty pieces for the top. You’ll need about 12-15 slices for the top.
- Use a big, shallow pan for baking to ensure even and quick cooking. We prefer a 9 x 13-inch baking dish or an 11-12 inch round baking dish.
- Press down on top of the gratin to prevent doming. You want to make sure the top of the gratin is level.
- Avoid letting the foil touch your food by adding a layer of parchment between the gratin and the foil. Foil can be toxic!
Meal Prep & Storage
Meal prep: This can be assembled ahead and baked the day of serving, bringing it to room temp before baking. Alternatively, this can be baked ahead and reheated in a low 325-350F oven, covered (also bringing to room temp before reheating).
Storage: Store leftovers in a sealed container in the refrigerator for 3-5 days.
Freezing: I have not tried freezing this recipe. My hesitation is it might get watery- but only guessing here. If you freeze this, please report back and let us know in the comments.
Serving Suggestions
While this is a popular Thanksgiving side dish, we love making this as a cozy fall and winter vegetarian dinner. Simply serve with a salad, like our Beet and Goat Cheese Salad or Pear Salad with Vanilla Fig Dressing, and our Sourdough Bread.
Be sure to check out our 55 Veggie-Powered Thanksgiving Side Dishes!
FAQs
Yes, I think so! Use vegan parmesan and a vegan cream or plant-based cream. Lite coconut milk from a can would taste good, I bet. Please let us know if you try this- leaving notes for others- thanks!!!
They are very similar, we simply swap the scalloped potatoes for butternut squash!
Use a sharp knife! It may also help to work with smaller pieces at a time. Try cutting between the top half and the portion with seeds. Then you have two smaller halves that can be easier to handle! You can try a mandolin, but a sturdy knife is usually better.
Give this Butternut Squash Gratin a try this Thanksgiving and let us know what you think (or ways you adapt it) in the comments below.
Cheers,
More Recipes You May Like
Butternut Squash Gratin Video
Butternut Squash Gratin Recipe
- Prep Time: 40 mins
- Cook Time: 60 mins
- Total Time: 1 hour 40 minutes
- Yield: 8
- Category: side dish, vegetarian
- Method: baked
- Cuisine: American
- Diet: Vegetarian
Description
This Butternut Squash Gratin is made with leeks, sage, and walnuts. It is a delicious fall side dish, 100% worthy of the holiday table! Vegan-adaptable and gluten-free. Video.
Ingredients
- 2 lb butternut squash, peeled, sliced to 1/8 inch disks.
- 2 tablespoons olive oil or butter
- 2 medium leeks, thinly sliced
- 4 garlic cloves, rough chopped
- 15 sage leaves, chopped (8 more for crispy sage leaf garnish- optional)
- ——
- 1 cup heavy cream (or sub coconut milk)
- 1/2 teaspoon salt and pepper
- 1/2 teaspoon nutmeg
- 1/2 teaspoon onion powder, optional
- ——-
- 1/4 cup water
- 3 ounces gruyere cheese (or sub parmesan or vegan parmesan)
- 1/2 cup walnuts, chopped
Instructions
Preheat oven to 375 F
- Prep Butternut: Peel and thinly slice the butternut squash into 1/8 -inch thick rounds. When you get to the seeds, scoop them out and continue slicing. Set aside 12-15 of the “prettiest” slices for the top of the gratin. ( There will be 3 layers of butternut – so you could divide into 3, placing any misshapen pieces in the middle layer)
- Cook the Leeks: Slice and rinse the leeks- the moisture here will help them soften. Heat oil or butter in a large skillet over medium heat. Saute the leeks, for 8-10 minutes, covering part way through so they soften. Add the garlic, sage and a pinch of salt, cook 2-3 more minutes. Turn heat off.
- Whisk the cream with the salt, pepper, nutmeg and onion powder in a medium bowl.
- Layer: Grease a large 9 x 13-inch baking dish or 11-12 inch round baking dish. A big shallow pan is BEST here ensuring even cooking. Grease the pan, add 1/4 cup water to the bottom of the pan. Layer with Butternut squash overlapping slightly. Sprinkle with half of the sauteed leeks. Drizzle with 1/3 cup cream mixture. Sprinkle with one ounce of Gruyere (about 3-4 tablespoons grated). Add the 2nd layer of butternut- using up any misshapen pieces here. Scatter with the remaining leeks. Drizzle with 1/3 cup cream mixture and sprinkle with grated gruyere cheese. Add the final layer of butternut, overlapping and pressing down so not domed in the middle. Drizzle the remaining cream mixture over top, lightly sprinkle with cheese and the walnuts. Give the pan a little shake, press down in the center again so gratin is level, not domed. Cover, using parchment first as a barrier, under the foil if the foil touches the top of the gratin.
- Bake 45 minutes covered. Uncover, confirming the butternut is tender using the tip of a knife, then bake at 400 F uncovered, 15 minutes until beautifully golden.
- To make the crispy sage leaf garnish, heat 1-2 tablespoons oil or butter in a pan over medium heat, add 8 whole sage leaves, saute each side 30 seconds or so until crisp (try a tester first) and place on a paper towel to cool for a couple of minutes. Arrange over the gratin.
Notes
This can be made ahead: Assemble ahead, refrigerate, and bake the day of serving, or alternatively, assemble and bake ahead, reheating the day of serving (350F, covered). Make sure to let this come to room temperature before baking or reheating, for most even cooking.
I have not tried this with cubed butternut, but if I were to go that route, I would toss them in a big bowl, with the cream mixture and leeks and cheese. Bake in a large shallow baking dish and allow 20-30 more minutes additional baking time depending on the size of the cubes. Thinly sliced butternut makes this bake relatively quickly- cubes would take longer, so plan accordingly. (Or you could lightly steam or cook them first?)
Nutrition
- Serving Size: – used heavy whipping cream and olive oil
- Calories: 201
- Sugar: 4.3 g
- Sodium: 239.5 mg
- Fat: 12.7 g
- Saturated Fat: 6.1 g
- Carbohydrates: 19.3 g
- Fiber: 3.1 g
- Protein: 5.4 g
- Cholesterol: 28.7 mg
Made this Butternut gratin with leeks for the 3rd time now. Just love it! I used coconut milk to keep it vegan and is creamy and delicious. Great flavour combinations as always from Sylvia. Easy to prepare too. Fast becoming our new midweek staple!
I made this last night and it was delicious! I will definitely be making this again and is the perfect dish for a special dinner. I used toasted sunflower seeds as I did not have walnuts, and it worked quite well.
This butternut squash gratin was superb. I plan on including this in my Thanksgiving spread moving forward. The addition of walnuts adds great texture to the dish – coming from someone who is not a nut lover. I will make this again and again.
do you think this would be good with rosemary if i can’t find sage readily? thank you so much !
I made the vegan version for Thanksgiving and it was perfection. A nice sweet side dish.
I found this recipe around Thanksgiving time, and tonight is my third time making it! It is an absolute hit. I have to eat gluten-free, and one of my flatmates has to eat dairy-free so finding delicious recipes has been a little more challenging, but this one is basically perfect 😁 I made it for family Christmas and it was the most complimented dish there!
I make it vegan with one whole tin of coconut cream, and have been just omitting the cheese but tonight I blended about a teaspoon of nutritional yeast flakes into the coconut cream for a cheesy flavour.
Thanks for sharing, great to hear!
I love this gratin! Have made it a few times now as a lovely warming winter meal. My husband loves it too. I use coconut cream as suggested and comes out beautifully creamy and delicious. Thanks Sylvia for another classic!
LOVED THIS!
will now be part of our standard celebration meal menu
This was an easy yet decadent side dish for our small Quarantine Christmas! I doubled the cheese.
Wasn’t sure if I should chop the sage as the recipe didn’t specify, but the photos gave me the impression that I should. Couldn’t hurt to edit the recipe if this is the case.
Thanks, fixed it. 😉
This was SO good! My family was not really looking forward to trying this dish, but it was universally liked and they asked for the recipe. I used a sweet meat squash instead. It was a pain to peel, but I didn’t lose any fingers, so all good. Thank you
Delicious! I made ours with half and half and heavy cream. Turned out great!
Made this and added panko on top because my family is all about crunch.What a winner! We swooned, we ooh’d and paired it w/ a simple salad and nice cava. Another favorite recipe from Sylvia!
So delicious that I stopped everything I was doing to analyze all the incredible flavors swirling around. Thank you so much Sylvia.
this was so delicious! made it vegan using coconut cream and skipped the cheese altogether. it was a winner!!
Oooooo love it! How much coconut milk did you add? Did you add water too? Thanks Paloma!
i used half a cup of coconut cream, it’s really thick like full fat cream so I mixed in about half cup of water (the texture turned out to be basically coconut milk). I also added water to the bottom of the pan but would skip this step next time because it came out watery at the bottom after cooking.
Thanks appreciate this!
Hi
I made this with coconut milk but the receipe was very watery. Is the additional water necessary with coconut milk?
Probably not, sorry.
This was SO GOOD! My husband made it for thanksgiving to go with our slow roasted goose and I’m now going to insist we cook it every year. It easily substitutes both mashed potatoes and yams—yum!
The ultimate cosy supper dish on a cold, dark and windy evening. Tasted amazing and the toasted walnuts added a lovely interesting texture. Used dried sage as couldn’t get fresh and served with salad and bread! Sublime! Thanks Sylvia
Divine!! Easy to make and such great presentation and flavour – the butternut is the key. Thanks again Sylvia, love your recipes✨
Another awesome recipe! I didn’t have any gruyere so used smoked cheddar instead. The leeks blended in so well with the smooth squash. There was a hint of nutmeg with the smokiness of the cheese. The walnuts were the icing on the cake. We ate this for dinner and it was so satisfying. Thanks again. I look forward to your recipes each week
OMG, sooooo good ! I did not have fresh sage, so i use sage pesto i had frozen. This will be redone again and again for sure. Thanks for all your great recipes, you are one of my best recipes website, if not the best !
Hi Sylvia…can you use Sweet potato’s instead of squash. I’m already making a squash dish and would like to use sweet potato’s in an interesting way.
I bet it would taste good with sweet potatoes too!
Can’t wait to make this!
Will try the butternut squash recipe.
Are there any options to not use so much fat in the recipes.
It’s just better for me health wise.
What if you used whole milk or nut milk?
So good! I didn’t know what to expect from this recipe. I’ve never cooked with leeks or fresh sage before and I don’t often use special cheeses. But everything came together very easily. I didn’t worry about arranging the squash just so – I used my kitchenaid slicer to whip through the veggies and so it wasn’t super pretty, but it worked well and it looked just fine in the end under the cheese. 🙂 I don’t suggest any tweaks – it was excellent. I’ll definitely be making this again.
Thanks so much and glad you liked this!
I’m really excited to make this for parties and dinners once things have settled down again. It looks delicious, and the vegetarian substitutions sound great! Quick question, how many walnuts did you use in this recipe? The directions don’t include how much, just that they were sprinkled in. Thank you!
Oooops! 1/2 cup walnuts- thanks, I added. 🙂