This butternut squash lasagna layers a whipped roasted squash sauce with sauteed mushrooms, spinach, and three kinds of cheese. It is rich, meat free, and sturdy enough to hold its own as the main dish on a Thanksgiving table! Assemble it ahead and bake it when you are ready.
More meatless lasagna recipes:
Before You Get Started
Three things separate a clean, sliceable lasagna from a soupy one. Get these right and the rest of the recipe is just assembly:
- Squeeze the spinach bone dry. Wring it out in a dish towel until no more water comes out. Wet spinach creates a runny filling.
- Roast the squash until tender. A fork should slide in with no resistance. Undercooked squash will not blend into a smooth, spreadable sauce.
- Let it rest 15 minutes. The cheese needs that time to set. Slice too soon and the layers slide apart on the plate.
How to Make Butternut Squash Lasagna
There are four components here, and none of them are difficult. The honest picture: about an hour of the total time is the squash roasting on its own while you do something else, and the active work is closer to 40 minutes. You can also split it across two days, which is covered below.
Step 1: Roast the Butternut Squash
Halve the squash lengthwise and scoop out the seeds. Rub the cut sides with olive oil, place them cut side down on a parchment lined baking sheet, and roast at 400°F for 50 to 60 minutes.
You are looking for very tender, not just cooked through. A knife should cut through with no resistance at the thickest part of the neck. This is what determines whether your sauce is silky or grainy.
Step 2: Whip the Squash Into a Sauce
Let the squash cool enough to handle, then peel off the skin and scoop the flesh into a blender or food processor. Add the milk, thyme, sage, salt, and pepper, and blend until completely smooth.
Taste it here. This sauce is standing in for the tomato sauce in a traditional lasagna, so it needs enough salt to carry the whole dish. Add more herbs if it tastes flat.
Step 3: Saute the Mushrooms and Onions
Melt the butter in a large skillet over medium high heat and cook the onions until soft, about 8 minutes. Turn the heat to high, add the mushrooms, thyme, and sage, and cook about 3 more minutes, until the mushrooms have released their liquid and it has cooked off.
Do not rush this part: Mushrooms that go into the pan still wet will keep releasing water in the oven.
Step 4: Mix the Ricotta and Spinach Layer
Squeeze every bit of liquid out of the thawed spinach, then stir it together with the ricotta, mozzarella, Parmesan, egg, salt, garlic powder, and nutmeg.
⇢ Do not skip the egg: It sets the cheese layer so it stays put when you cut into the pan. If you need to leave it out for an allergy, the flavor holds up but the slices will be looser.
The nutmeg is a small amount and easy to dismiss, but it adds essential savory depth to a squash and cheese filling.
Step 5: Layer and Assemble
Spread about ¾ cup of squash sauce across the bottom of a greased deep 13 x 9-inch dish. That thin base layer keeps the first sheet of noodles from sticking and drying out, so do not skip it.
Then build: noodles, half the ricotta mixture, half the mushrooms, a heaping cup of squash sauce, noodles, the rest of the ricotta, the rest of the mushrooms. Finish with any remaining squash, then the mozzarella and Parmesan.
⇢ Using regular noodles instead of no-boil? Drop the oven to 375°F. The same goes for homemade sheets, which cook faster than the boxed no-boil kind.
⇢ Cooking for two? Split everything between two 8-inch square dishes. Bake one now and freeze the other, same effort, two dinners.
Step 6: Bake Covered, Then Uncovered
Cover the dish tightly with foil and bake at 400°F for 25 minutes. Remove the foil and bake about 15 minutes more, until the filling is bubbling at the edges and the cheese on top is browned in spots.
The foil is important in the first half. It traps steam so the no-boil noodles hydrate properly and the squash sauce does not dry into a skin. Pull it too early and you get crisp noodle edges instead of tender ones.
Step 7: Rest Before Slicing
Let the pan sit for at least 15 minutes. Garnish with chopped fresh herbs, extra Parmesan, or a pinch of red pepper flakes if you like a little heat.
Try it another way
Have more squash than you need? My Butternut Squash Casserole with Apples is a good way to use the rest.
What to Serve Alongside
This is a rich, filling main dish, so what it needs most is something bright and something to mop the plate with. A crusty bread and a sharp, acidic salad are all it takes to make a full meal.
If you are serving it as the meatless main at a holiday table, it has one real advantage over most entrees: it holds beautifully at room temperature for 20 minutes while everything else comes out of the oven.
- Homemade Garlic Bread (the easiest and most obvious pairing)
- Focaccia Bread Recipe
- Easy Homemade Dinner Rolls
- Fennel Salad with Apples and Creamy Cider Dressing
- House Salad with Candied Pecans
- A simple green salad with Red Wine Vinaigrette (the sharpest option and my pick to balance all that cheese)
Storage and Make-Ahead
This recipe is built for making ahead, which is most of the reason it is worth the effort in the first place.
To make ahead: Assemble the lasagna but do not bake it. Wrap the dish tightly in plastic wrap and then foil. It will keep in the refrigerator for up to 48 hours, or in the freezer for up to 3 months.
You can also break the work across two days. Roast and puree the squash on day one, refrigerate it, and assemble everything on day two. That turns a long afternoon into two short ones.
To bake from the fridge: Let the dish sit on the counter for 30 to 60 minutes to come to room temperature, then bake as directed.
To bake from frozen: Bake covered at 400°F for 1 hour, then uncover and bake another 10 to 15 minutes, until the pasta is tender and the center is hot.
To store leftovers: Keep them in an airtight container in the refrigerator for 3 to 4 days, or freeze for up to 3 months.
To reheat: Cover loosely with foil and warm in a 350°F oven for about 30 minutes, until heated through. Individual slices reheat in the microwave in 30 to 60 seconds.
Frequently Asked Questions
Do I have to use no-boil noodles?
No. No-boil noodles are what I use because they save a step and there is already plenty going on here, but regular lasagna noodles work well. Boil them first, and drop the oven temperature to 375°F so they do not overcook. Homemade lasagna sheets work too, with the same lower temperature.
Why did my lasagna turn out watery?
Almost always the spinach or the mushrooms. Frozen spinach holds far more liquid than it looks like it does, so keep wringing it out in a dish towel past the point where you think you are done. Mushrooms need to cook until the liquid they release has evaporated, not just until they soften.
Can I use fresh spinach instead of frozen?
Yes, but you will need a lot of it. A 10 ounce package of frozen chopped spinach equals roughly a 1 pound bunch of fresh, and buy a little extra since trimming the stems cuts the weight. Cook it first, drain it, and squeeze it dry before it goes into the cheese mixture.
Can I substitute cottage cheese for the ricotta?
Yes. Use small curd or whipped cottage cheese for a lighter layer, and strain it first if it looks watery in the tub. Cottage cheese is saltier than ricotta, so cut back slightly on the salt in the filling.
Can I use sliced butternut squash instead of the lasagna noodles?
You can, and it makes a lighter, lower-carb dish. Slice the squash into long thin planks, roast them until just tender, and layer them in place of the noodles. Just know that squash releases moisture as it bakes, so the result is softer and does not slice as neatly as a traditional lasagna.
More Lasagna Recipes to Try
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Roasted Butternut Squash Lasagna
Ingredients
For the butternut squash layer:
- 1 large butternut squash (about 3 ½ to 4 pounds)
- 1 to 2 tablespoons olive oil
- ⅔ cup milk
- 1 teaspoon fresh thyme leaves (or ½ teaspoon dried thyme leaves)
- 2 fresh sage leaves (or ¼ teaspoon dried sage)
- ¾ teaspoon kosher salt
- Dash of ground black pepper
For the mushroom layer:
- ¼ cup (½ stick) salted butter
- 2 large yellow onions, thinly sliced
- 8 ounces sliced baby bella or white button mushrooms
- ½ teaspoon chopped fresh thyme leaves (or ¼ teaspoon dried thyme leaves)
- 1 fresh sage leaf, chopped (or ⅛ teaspoon dried sage)
- Kosher salt and ground black pepper, to taste
For the ricotta spinach layer:
- 1 (10 ounce) package frozen chopped spinach, thawed
- 15 ounces ricotta cheese (or 16 ounces small curd cottage cheese, extra liquid strained)
- 1 cup shredded mozzarella cheese
- ¼ cup grated Parmesan cheese
- 1 large egg, lightly beaten
- ½ teaspoon kosher salt
- ½ teaspoon garlic powder
- ⅛ teaspoon ground nutmeg
For assembling:
- 1 (12 ounce) package no-boil ("oven ready") lasagna noodles (you will probably not need the whole box, I use 10 noodles)
- 1 ½ cups shredded mozzarella cheese
- ¼ cup grated Parmesan cheese
- Optional garnish: chopped fresh parsley or other herbs
Instructions
- Preheat oven to 400°F. Grease a deep 13 x 9-inch baking dish and set aside.
Prepare the butternut squash:
- Slice the squash vertically down the center and scoop out the seeds. Rub olive oil all over the squash and place the halves cut side down on a parchment lined baking sheet. Roast for 50 to 60 minutes, until a knife slides into the thickest part with no resistance.
- Let the squash cool, peel off the skin, and transfer the flesh to a food processor or blender.
- Add the milk, thyme, sage, salt, and pepper. Blend until completely smooth, then taste and adjust the seasoning. Set aside.
Prepare the mushrooms:
- Melt the butter in a large skillet over medium high heat. Add the onions and saute until soft, about 8 minutes. Increase the heat to high, add the mushrooms, thyme, and sage, and cook until tender and the released liquid has evaporated, about 3 more minutes. Remove from the heat and season with salt and pepper to taste. Set aside.
Prepare the ricotta spinach layer:
- Squeeze all of the liquid out of the spinach. A dish towel works best here, and you want to keep wringing until no more water comes out. Place the spinach in a large bowl.
- Add the ricotta, mozzarella, Parmesan, egg, salt, garlic powder, and nutmeg. Stir well with a fork to combine.
Assemble the lasagna:
- Spread about ¾ cup of the butternut squash mixture across the bottom of the prepared dish. Top with a single layer of no-boil noodles, then half of the ricotta mixture and half of the mushroom mixture.
- Add a heaping 1 cup of the squash mixture, another layer of noodles, the remaining ricotta mixture, and the remaining mushrooms.
- Spread any remaining squash on top. Finish with 1 ½ cups shredded mozzarella and ¼ cup grated Parmesan.
- Cover the dish tightly with foil.
- Bake for 25 minutes. Remove the foil and bake about 15 minutes more, until the filling is hot and bubbly and the cheese on top is nicely browned.
- Let stand at least 15 minutes before slicing and serving. Garnish with additional chopped fresh herbs if desired.
Notes
- Squeeze the spinach completely dry. Frozen spinach holds far more water than it appears to, and it is the most common cause of a runny lasagna.
- Roast the squash until very tender. If it does not blend perfectly smooth, it was not roasted long enough.
- Cook the mushroom liquid off before assembling, or it will end up in the finished dish.
- The egg matters. It sets the ricotta layer so the slices hold together. Omit it for an allergy if you need to, but expect looser slices.
- Using regular or homemade noodles instead of no-boil? Boil regular noodles first, and reduce the oven temperature to 375°F for either.
- Cover with foil for the first 25 minutes. This steams the no-boil noodles tender and keeps the squash sauce from drying out on top.
- Rest for at least 15 minutes before cutting so the cheese sets.
- To make ahead: Assemble without baking, wrap tightly in plastic wrap and foil, and refrigerate up to 48 hours or freeze up to 3 months. You can also roast and puree the squash a day early and assemble the next day.
- To bake from the fridge: Bring to room temperature on the counter for 30 to 60 minutes first.
- To bake from frozen: Bake covered at 400°F for 1 hour, then uncover for 10 to 15 minutes more.
- To store: Refrigerate leftovers in an airtight container 3 to 4 days, or freeze up to 3 months.
- To reheat: Cover loosely with foil and warm in a 350°F oven about 30 minutes. Individual slices reheat in the microwave in 30 to 60 seconds.
- Cooking for two? Divide between two 8-inch square dishes, bake one and freeze the other. Baking instructions stay the same.
- Substitution: Small curd or whipped cottage cheese works in place of ricotta. Strain it if watery, and cut back slightly on the salt.
Nutrition
Originally published in November, 2022, this post was updated in October, 2026.
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Here’s to the next 10 +
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Thank you, Leslie!