This vegetarian acorn squash pasta sauce is made with roasted squash and onion, milk, and butter for an easy fall béchamel sauce. Serve it with your favorite pasta!

It's rainy and cold outside, and it seems like the perfect day to enjoy some warm, savory winter squash.
Admittedly, I don't need much of an excuse to eat squash.
Really, we've had so much winter squash!
This fall we've been enjoying lots of roasted spaghetti squash (and Instant Pot spaghetti squash!) in spaghetti squash marinara, spaghetti squash gratin and this salmon spaghetti squash bake.
We've also been eating beer cheese soup (with butternut squash) and delicata squash salad.
I just can't get enough!
The winter squash we have the most of, though, is acorn squash. Our winter food storage area is filled with acorn squash!
Typically, I make roasted acorn squash slices served with cranberry sauce. This time, though, I had so much squash on hand that I wanted to try something new.
This acorn squash pasta sauce is inspired by the sauce in my butternut squash lasagna, and is a rich, thick sauce that's perfect for tossing with your favorite pasta.
Looking for even more winter squash recipes? Try making butternut squash quiche, butternut squash galette, spicy butternut squash soup, and roasted delicata squash.
How to Prepare Acorn Squash
To get your squash ready, you'll want to cut it in half.
I usually cut across the middle, but you can also cut from pole-to-pole (top to bottom). For this recipe, it doesn't matter which way you cut it.
Winter squash can be tricky to cut. Here's how I do it.
Use a large chef's knife and stick the knife point into the squash. Slowly rock the knife back and forth until a slit appears.
At this point, you can use more pressure and cut the squash totally in half.
Next, use a spoon or a scoop to remove the seeds and membrane.
Roast the Acorn Squash + Onion
Place the acorn squash and a wedged onion onto an oven-safe pan or a baking sheet. I used this Lodge 12" carbon steel skillet.
Season with paprika, chili flakes, nutmeg and sea salt.
Roast until the squash is tender.

If you want, you can roast the onions and squash ahead of time. Store them in the fridge for up to two days until you're ready to proceed.
How to Make Acorn Squash Pasta Sauce
Next, scoop the squash out of the peel.
Be careful if the squash is still hot!
Blend the onion and squash with milk. Set the mixture aside.

Next, melt butter in a large pan.
Whisk in a little flour. Gluten-free all purpose flour (such as Cup 4 Cup) works perfectly here, so use that if needed.
Continue whisking until there are no more lumps of flour.

Pour the squash mixture into the butter and whisk it together.
Heat the mixture until it thickens.

At this point, the sauce is almost ready!
Add a splash of wine vinegar to add acidity. Taste the sauce and add more salt or chili flakes if desired.
Serve it right away along with your favorite pasta and a little Parmesan or Asiago cheese, or store it in the fridge to use later.

Acorn Squash Pasta Sauce
Equipment
Ingredients
- 2 pounds acorn squash, halved with seeds + membrane removed
- 1 onion, peeled + cut into wedges
- 2 tablespoons olive oil
- 1 teaspoon sea salt
- 1 teaspoon paprika
- 1 teaspoon red chili flakes
- ¼ teaspoon nutmeg, freshly grated
- 1 cup milk
- 2 tablespoons butter
- 1 tablespoon flour Use gluten-free AP flour if needed
- ¼ ounce wine vinegar
Instructions
- Preheat oven to 400°F.Place squash + onions on a baking sheet or oven-safe pan in a single layer. With squash flesh-side up, drizzle oil over squash and onions. Sprinkle with salt, paprika, chili flakes and nutmeg. Place squash flesh-side down.Roast 20-25 minutes or until tender.
- After cooking, carefully scoop the squash out of the peel. (You may need to allow the squash to cool down for a few minutes.)Add half the vegetables and all the milk to a blender basin. Blend until creamy. Add the remaining veggies and blend again.
- Add butter to a large pan and melt over medium heat. Whisk in the flour until it is completely absorbed by the butter.
- Add the puréed squash to the pan with the butter. Cook over medium heat for about two minutes, stirring often, and then remove from heat. Stir in the vinegar.Serve immediately along with fresh pasta or refrigerate and use within four days.
Mary Beck says
Thank you for this. I recently learned that I have a nightshade intolerance, so I've had to cut out tomatoes, potatoes, peppers, and eggplant from my diet. Obviously, with that information, I didn't add all the ingredients. No paprika or chili flakes for me. But it was still very tasty. I used it in a lasagna along with some zucchini slices and cottage cheese, and it was perfect! I'm so glad people like you are making my time easier. I'm so grateful. I'm going to try a few ideas with seasonings. Would you like to know any of my findings? Thank you again.
Sarah Trenalone says
I'm so glad you liked it Mary! I'm happy to help 😀
And sure, let me know what other seasonings you tried!
Mary D Beck says
So, I used garlic salt (since there's already onions and usually I use onion salt), marjoram (which is a great substitute when making taco meat), and coriander. All of it has a hefty flavor. More marjoram makes it taste a bit more like tacos, but the coriander mixed in makes it taste more like pasta sauce. I'm still experimenting with seasonings, since they aren't usually labeled as nightshade or not.
Sarah Trenalone says
That sounds delicious!! I'm so glad you enjoyed 🙂
Aamina says
Just made this for dinner with 1 major modification, based on what I had in my fridge: half of a roasted acorn squash (leftover from another recipe) and half each of 1 red bell pepper, 1 yellow bell pepper, and 1 orange bell pepper (also all leftover from the other recipe). I roasted the bell pepper halves with the onion, then sauteed them with the acorn squash, the spices, and some broth, to soften all of it further. Added the roux, then the milk, and blended with a hand blender.
The one thing I wish I'd omitted was the vinegar (I had only white vinegar on hand) - unnecessary, and made the sauce too sweet. But it was still good! Parmesan on top was nice.
Alisha Trenalone says
Hi Aamina 😊 If you added distilled white vinegar (not white wine vinegar), that’s a lot stronger than wine vinegar, so a lemon might’ve been a better swap. But glad you enjoyed it otherwise!
-Alisha at Champagne Tastes
Meghan says
Can you make the sauce then let it cool and freeze it? I’m wanting to make this for my baby but she’d only need a small portion at a time. I was thinking of freezing small batches in an ice cube tray.
Alisha Trenalone says
Hi Meghan! We typically don't test sauces like this in the freezer because when they have milk it may not reheat the best. That said, you could try swapping in a little vegetable broth instead of milk, and then freeze it. You could add a bit of milk when you go to re-heat.
-Alisha at Champagne Tastes
Brandi G says
If I use oat milk, can this be canned for long term storage?
Alisha Trenalone says
Sorry, we haven't tested this recipe with canning. We have tested with freezing, though -- check the recipe card notes for freezing instructions.
-Alisha at Champagne Tastes
M says
Very good! I don’t know how much the roux adds to be fair. I added a pack of silken tofu to the blender for extra protein and it worked well. Thanks!!
Alisha Trenalone says
Glad you enjoyed it!
-Alisha at Champagne Tastes
Maribel says
This sauce was delicious!