Butternut Squash Pasta Sauce

I’ll be honest, I didn’t have high hopes the first time I made this Butternut Squash Pasta Sauce. A pasta sauce built from squash, a couple of tomatoes and half an onion sounded like something you’d eat because it was good for you, not because you wanted it. Then I blended the roasted vegetables with a splash of hot pasta water and it turned glossy and genuinely creamy, and I stood at the counter eating it off the spoon.

There is no cream in this butternut squash pasta sauce. No milk, no cashews, nothing blended in to fake it. Roasting the squash at 450°F concentrates its sugars and drives off water, and the starch in the reserved pasta water pulls it all together into something silky. That’s the whole trick. I use a bag of frozen diced butternut squash, which means no wrestling a whole squash with a knife.

It’s been on this site since 2021 and it’s STILL one of my fall favorites! One batch sauces a pound of pasta with enough left over to freeze, which is how it usually goes in our house.

Why you’ll love this recipe

• Creamy without cream! – the butternut squash caramelizes while being roast in the oven leaving you with a rich, creamy pasta sauce without any heavy cream. This sauce is completely vegan!
• Frozen veggie shortcut – I usually use frozen, cubed butternut squash in this recipe to save myself time and frustration. Cutting into a fresh butternut squash is A LOT of work.
• Great for kids – my toddler boys can be tricked into thinking this is mac and cheese thanks to the bright orange flavor. I sometimes even use macaroni noodles to really entice them to eat a sauce that is loaded with veggies.

For another roasted veggie sauce, you can try this roasted veggie pasta sauce next.

Ingredients you’ll need

You will be amazed at how easy it is to make this healthy butternut squash pasta with just a few simple ingredients.

• Frozen cubed butternut squash (16 oz bag) — the whole reason this is a weeknight recipe. No peeling, no wrestling a hard squash with a big knife, no 40 minutes of roasting. Roast it straight from frozen, don’t thaw it first — thawed squash sits in its own water and steams instead of browning, and browning is where the sweetness comes from. Fresh works too: peel and cube it into ¾-inch pieces and you’ll need about 4 cups to match the bag.
• Fresh chopped tomatoes (1½ cups) — these bring the acidity that keeps the sauce from tasting like baby food. Squash alone is sweet and one-note; the tomatoes give it a backbone. Cherry or grape tomatoes are my favorite here because they’re reliably sweet year-round and they collapse into jammy little pockets on the sheet pan, but any ripe tomato you have works. Roma holds up well. Out of season, a cup of canned diced tomatoes, drained, will do the job.
• Yellow onion (½ onion) — roasted alongside everything else until the edges go golden and sweet. Don’t dice it small; big chunks hold up to the high heat without burning, and it all gets blended anyway. A shallot is a slightly sweeter, more delicate swap, and red onion works in a pinch.
• Olive oil (2 tablespoons) — it does more than stop things sticking. The oil carries heat into the surface of the squash so you get real caramelization instead of a pale roast, and it stays in the sauce, which is part of why it tastes rich without any dairy. Toss everything until it’s evenly coated.
• Salt, pepper and dried thyme (1 tsp salt, ¼ tsp pepper, ½ tsp thyme) — season the vegetables before they go in the oven, not after blending. Salt pulls moisture to the surface where it can evaporate, and seasoning early means the flavor is in the vegetables rather than sitting on top of the sauce. Dried thyme is the right call over fresh here: it’s woody and holds up to 450°F, where fresh thyme would just scorch. Dried sage or rosemary both work if that’s what’s in the cupboard, and a few scrapes of nutmeg is a classic pairing with squash if you want it to taste a little more autumnal.
• Pasta (1 lb) — shape matters more than usual with this sauce. I use radiatori, because all those ruffles catch and hold a thick blended sauce. Rigatoni, shells, fusilli, cavatappi and orecchiette all work for the same reason. Long thin pasta like spaghetti or angel hair is the one I’d avoid; the sauce slides off instead of clinging. Salt the cooking water well — it’s your only chance to season the pasta itself.
• Reserved pasta water (⅓ cup) — don’t skip this one. The starch that comes off the pasta is what turns blended vegetables into a glossy sauce that coats every noodle instead of sitting in a puddle at the bottom of the bowl. It’s the single most important ingredient in the recipe and it’s free. Scoop out a full cup before you drain, even though you only need a third — you’ll want the extra to loosen the sauce if it thickens up, and there’s no getting it back once it’s down the drain. Plain hot water will work in an emergency, but it won’t be as silky.

How to make this butternut squash pasta sauce

Step 1: Toss butternut squash, tomatoes and onion in olive oil and seasonings. Roast in the oven at 450F until tender. Boil pasta in salted water and reserve pasta water.

Step 2: Pour roasted vegetables into a blender with the starchy pasta water.

Step 3: Blend sauce until extra smooth.

Step 4: Pour creamy blended sauce over the noodles and toss to coat each noodle evenly.

Storage, Freezing and reheating Instructions

In the fridge: the sauce keeps up to 7 days in an airtight container. Store the sauce and the pasta separately if you can — pasta sitting in sauce keeps absorbing it and turns soft and a little pasty by day two. It will thicken in the fridge, which is normal. Reheat it gently with a splash of water, stock or milk and stir until it loosens back up.

In the freezer: this sauce freezes beautifully, and it’s the main reason I make a full batch even when I’m only feeding two of us. Freeze the sauce on its own, never tossed with pasta — cooked pasta goes mushy and grainy after a freeze and thaw, and there’s no rescuing it.

One batch makes about 3 cups of sauce, which is enough for a pound of pasta. Two ways I portion it: