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
This is delicious, better than the best restaurant in town according to my family! I used parmesan and went heavy on it, did not add the walnuts this time.
Glad you liked this Josie! Appreciate you taking time to let us know. 🙂
I made this on the day, for entertaining once and it was lovely, but the cooking smell got into my clothes, just when I was having guest. So the next time I made it ahead and froze it, but was disappointed when I cooked it. because the cream seem to seperate and left it watery with glups of fat floating in it when you dug in. Has anyone else froze it, because I love the recipe.
If you look in the comments there are others who have frozen it with less than perfect results. I think you could assemble it the day before, refrigerate and bake to serve. Let it come to room temperature first.
I made this dish for Thanksgiving-and it was delicious!
Glad to hear Kathy!
Made this for Thanksgiving, and there were not many leftovers! Very easy to prepare, and looked great on the table.
Excellent to hear this Scott!
We made the vegan version. Very tasteful ans actually easy to make.
Yum!
Great to hear this Virginie!
Love to try this recipe for everyday side dishes. Can you half this recipe and be successful. Only 2 people in my household.
It should work just fine Carmen!
Cubed butternut came out great and was a faster prep for a weeknight dinner. Bought a bag of already cubed butternut. I just needed an extra 10 min for cook time.
Thanks. I just love your recipes and recommend them to many of my patients.
Thanks so much Liz!
So tasty and delicious. Love the walnuts on top! Great idea. Also made the crispy sage leaves. Very lovely 😊
So glad you enjoyed Kendall!
This is a fantastic recipe. Thank you.
Great to hear Chris!
This was easy and delicious! I didn’t have a few items (leeks, sage, Gruyère, and walnuts!) so I substituted a white onion, dried herbs, Parmesan, and pecans…my husband LOVED it and we will definitely make it again. Could do for everyday OR company! Thanks for a new favorite recipe!
Such a beautiful demonstration of adapting! So glad it worked out and you all enjoyed!
Outstanding. Turned out perfectly delicious. Sub’d pecans.
Wonderful to hear!
Simply awesome! A great addition to a Holiday meal with friends
Glad you enjoyed!
Excellent!
Hi Sylvia,
Do you it would be possible to mix butternut squash and potatoes in this recipe? I want to do potato au gratin and this wonderful butternut squash recipe so I wonder if it would be a good combo or it may not turn out the best? Thanks for the insight!
It sounds good to me! I guess my only hesitation is if they would cook in the same amount of time? Seems like it should be fine?
I’m going to try making this for my future daughter in law for Thanksgiving. She is a vegetarian and I want at least a couple of special dishes for her. This sounds amazing! I’m going to try it out at home first!
That is so nice Kathy, let us know how it goes!
Wonderful combination of the butternut, leeks,sage, walnuts, cheese. I did an “skinny” weeknight version by just baking it with the leeks butternut, a bit of broth instead of water, skipped the cream. Baked till done then on each serving could add as much or as little cheese as wanted. This was a great side dish. I would do it the way you have done for a special dinner though. A favorite.
Thanks Frances, love that you altered it to suit your preference.
Made it vegan! It was excellant.
I used blue ribbon plantbase cooking cream.
Violife grated mozzarella (could not find parmasan)
I had friends over for dinner and they loved this. I will making it again.
Great to hear jacqi
This recipe is simply exquisite — except for one problem: the water added to the bottom of the pan was unnecessary and nearly ruined my gratin by making the bottom very watery and sludgy. (I’d even used a bit less water than called for.) I was able to save it by serving half with a slotted spatula and then leaving the pan resting at an angle to drain the remaining half before transferring it to a storage container. Other than this issue, it came together beautifully! The flavors are to die for, and I’m looking forward to making it for company sometime. Thanks!
Thanks Rina, not sure about the extra water… sorry about that.
I can’t explain that part, either, but your recipe is one of my top 3 favorite butternut dishes. (Your roasted butternut soup is another!) 3# of sliced squash, 3 leeks, and 1.5c cream fit my 9×13″ pan perfectly.
I think I see where there is confusion about the water. In the preamble discussion on how to make the recipe you state put some of the cream mixture in bottom of dish. In the recipe section there is no mention of this but it states to put water in the buttered dish and then start layering. I’m making this for company tonight so hopefully not adding the water works😬🤞🏼🙏
Cindy- please follow the recipe card for the best outcome. Hopefully it worked for you!
Yes I did add the water as the video I finally was able to view also showed adding the water. The recipe was delicious and turned out wonderfully.
Oh good! Ok whew, glad it worked well for you. 🙂
Hi there, I find my “just picked” butternut to be more watery then an aged/cured one. Also this year up here in VT rain was plentiful. The dryer squash perhaps need the extra moisture? (Also the leeks need their moisture cooked out, the video does a nice job on that!)
I’ve never thought of that Michelle! Good points!