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
Changed to vegan per the suggestions made and it was really good. I will definitely make again!
Great to hear Elise!
Omigod this is the most incredible recipe! It’s so light yet complex in flavour, I actually could eat the whole thing in one. I made this as one of my holiday recipes, a couple of days after making a potato gratin and I much preferred this recipe as it was far less heavy and yet ten times more flavourful. Thank you for your wonderful recipes!
Glad you enjoyed this Ciara!
Another hit! I made this with coconut milk and subbed parmesan for the Gruyère. I also used a little mozzerella because I had it on hand. It was so good and tasted so much like scalloped potatoes! I loved the sage and walnut in it. It was a great side for our simple thanksgiving dinner and was easy to throw together the day of!
Great to hear Eva!
We enjoyed your dish on Thanksgiving. I made a vegan version with lite coconut milk and we enjoyed your recipe. Next time I will just add a little more of the nutritional yeast flakes to give it a more cheesy kind of flavor. Leek is a staple in German kitchens, I was excited to see leek as an ingredient in your recipe smile. I will explore your other recipes and look forward cooking this recipe again. Thank you from Ingrid and Family
So happy you gave this a go. Yes, we love leeks too!
Hi, I made your recipe yesterday and we enjoyed it. I used a lite coconut milk, with the seasonings and made vegan Parmesan. Next time I will add additional nutritional yeast flakes to get some more cheesy flavor. I am from Germany and leek is a staple in the kitchen. I was glad to find your recipe!
Thanks so much Ingrid!
Hello, I’m looking to substitute sweet potatoes for the butternut squash. Do you think it will require the same baking time? Thank you
Great question, I’m not sure here. My guess is it would be close. But test with a knife when you remove foil to be sure.
Hi, can this be frozen at any stage? Am guessing not before its cooked, but maybe after? And maybe add the walnuts and crispy sage when you re-heat? What do you advise, please?
Hi Jane- I would freeze it after it is baked- and like you said add the nuts and sage after. That’s what I would do too. 😉
Haven’t yet made it—it looks and sounds great! I just wanted to mention to you that the recipe portion specifies to cut the squash in 18 inch thick pieces—when 1/8 inch thick pieces is meant.
Opps! thanks David, fixed it!
Hi Sylvia, if we wanted to add crumbled sausage to this, would we just mix it in raw with everything else? Or would you recommend cooking it first?
Just want to make sure it would be fully cooked when the veggies are. 🙂
Thank you! We’re huge fans of all your recipes.
Cook it first Claire, brown it, drain off the fat, then tuck it in and bake with the Gratin. 🙂
Delicious! I used pecans instead of walnuts. I plan to use this as a holiday side in the future.
Perfect!
Hi Sylvia, I made this last night, simply delicious. I replaced the walnuts with pecans.I decided to freeze the leftovers, I hope everything will turn out well. Thank you for another great recipe.
Thanks and great to hear Carole- let us know how it turns out after you thaw it…curious!
AM interesting in batch cooking some and freezing portions….how did the frozen portion turn out re-heated, please?
I’ve made this several times now and always really enjoy it. Thank you!
Other than parmesan, do you have any suggestions to substitute the gruyère? It is unfortunately very expensive where I live. And I like to use a lot 🙂
I tried freezing it as leftovers in portions and it turned out a little bit mushy but still flavourful. I didn’t mind eating it as leftovers after freezing but I don’t think I’d choose to freeze it if I wanted to serve it to guests or something.
For those who, like me, don’t care as much about the aesthetics and get tired of chopping, I have had good results quartering the solid parts of the squash and running them through my kitchen aid’s slicer attachment to speed up the process. They come out less pretty and a bit thinner but it saves me lots of time.
You know- I bet most meltable cheese would be ok here. Mozzarella, even maybe some goat cheese?
Hi – I am going to make this for Christmas as a side. If I make ahead and reheat at 350- how long do you think it needs to reheat for? Just trying to time everything! Thanks!
If you let it come to room temp first, probably 25-30 minutes? Perhaps cover with foil for first half?
Ok thanks! Love your website!
Has anyone added meat to this recipe? I was thinking of some crumbled Italian sausage? Thoughts?
I used your recipe for my first time cooking with butternut squash, and it turned out great. One thing I wondered – should I actually whip the heavy cream with the other ingredients, or simply combine and leave liquid? Some of it started whipping when I mixed it up.
My partner commented that she would like this gratin inside ravioli, so I’m trying to figure that out next 🙂
I think a good stir is enough here. This would be excellent inside Ravioli!
I made the vegan version and loved it! I added nutritional yeast to the coconut cream as suggested (thanks for that!) and was very happy with the outcome. I also used the remaining coconut water from the can instead of water. Thanks for another delicious and healthy recipe, Sylvia!!
Thanks Leanne!
Unanimous favorite at our Family Feast! Thanks Sylvia!
Great to hear- thank Kim!
There are no instructions for toasting the walnuts. Won’t they toast as part of the baking? Has anyone tried this with pecans instead? Anyway, made this 2x now and it is DELICIOUS. Now my go to for fall and winter gatherings. Thank you so much!!!
Yes, you are right, just use raw nuts, they will toast on top. Pecans are great here too!
This recipe turned out delicious!!! However the milk (I used half and half) curdled while baking. It still tasted fantastic, however the curdled milk was a little weird. Any suggestions on how to avoid this? The half/half came right out of fridge. Was it too cold? Should milk be brought to room temp before using? It came out of the fridge cold and I baked as soon as I assembled it. Any thoughts on how to avoid this? I’m making it for Thanksgiving, I know it taste delish, just need to solve that issue. Thank you!!!
Hi Elisabeth, it was the half and half. Sorry about that. The heavy creamy won’t curdle. Neither will the coconut milk. I removed the half and half as an option. Again, my apologies.
Ah! Okay. Hmmm I don’t have heavy cream and store not open tomorrow, I do have plenty of coconut milk though. The canned kind. That will work? And does it give it a different taste? I have to say, the recipe was delicious…just a
bumpy : )
Canned coconut milk will work great. Or you could try making a light bechamel sauce out of your half and half. I haven’t tried heating it, so that might work too.
Thank you so much for your quick response. I’ll give the coconut milk a try! I love your website and it is my “go to” for recipes. Happy Thanksgiving!
Let me know how it turned out Elisabeth!
I used coconut milk this time and it turned out fabulously!!!! It was a huge hit on Thanksgiving, delicious, and will be making this dish for a long time to come. Everyone asked for the recipe! Thank you so much!
Glad you enjoyed this- yes the coconut milk is lovely here!
I love this recipe! My second time making it and I’m sure I’ll be making it many times more. Thank you!
Thanks Joyce- glad you enjoyed it.
This looks delicious! I am making it for Thanksgiving. I just wanted to confirm the correct amount of butternut squash; is the weight given in the recipe after peeling and prepping it, or is that the weight of the whole squash? I just put my whole squash on the scale and it weighs 4.1 pounds. Thank you!
Hi Beth! Good question. And I’m trying to remember! I think it would be safe to say, 2 lbs peeled and deseeded!
Thank you! The walnuts are toasting as I type and I am about to break down the squash. Thank you so much for sharing this recipe! Have a wonderful Thanksgiving.
thanks Beth! You too!
Absolutely wonderful easy impressive tasty side dish that could be used for many occasions. Used homegrown squash and herbs from my garden. Great re heated up for leftovers for the next few days, Made a day ahead and served with Lamb Shanks. Thanks Sylvia.
Thanks Cheryl!
This is one of the best recipes with butternut squash! I have made so many variations and all are delicious. The last one was with blue cheese and cashew cream with smoked paprika and it was amazing. Thanks so much Sylvia!
Yum! Glad you are enjoying this.
Ridiculously good. And surprising the layers of flavor profiles. Absolutely a keeper recipe!
Thanks Alison! Glad you enjoyed this!
Made this last night for dinner. So delicious!!!
Glad you enjoyed this Donna!