Preheat oven to 425°F. Line a large baking sheet with parchment. Place the butternut squash, onions and garlic on the baking sheet. Drizzle with olive oil and season with salt and pepper. Roast until squash is lightly caramelized and golden, about 30 minutes.
While the butternut squash is roasting, cook the pasta in a pot of salted water according to package instructions until al dente. Drain, reserving ½ cup of the cooking liquid.
Transfer the roasted butternut squash to large saucepan. Add the vegetable broth, milk and pasta water, and use an immersion blender to blend until smooth.
Add the cooked pasta to the butternut squash sauce and toss to combine. Serve warm with grated parmesan cheese and chopped parsley, if desired.
Video
Notes
Storage: Store any leftovers in an airtight container. They will last about 3-4 days in the fridge.Freezing Instructions: You can also freeze the sauce for up to 3 months if you decide to only use half of it. Just allow it to cool completely, then transfer to a freezer safe container, making sure to leave room for expansion. I would not recommending freezing the pasta with the sauce though.Make Ahead Tips: You can make sauce up to 3 days in advance. When ready to use, reheat on a skillet adding more milk or pasta water as needed. Then toss in the cooked pasta. Substitutes: For best results, follow the recipe as is. However here are some common substitutes that would work well in this recipe.
Instead of vegetable broth, you can use more milk or more pasta water or a combination of the two.
Instead of milk, you can use heavy cream for a more creamy consistency, unsweetened almond milk for a plant-based version or more vegetable broth for
Instead of spaghetti, you can use any pasta of choice.
Equipment: I love using my Cuisinart Smart Stick hand blender for blending sauces. It's quick and easy and gets me the perfect consistency, without any chunks of vegetables leftover. And it's easier to transferring the ingredients in batches to a blender.