This butternut squash pasta is creamy, without a drop of cream — roasted squash blended with caramelized onion, butter and Parmesan is all it takes to make a velvety and deeply savory sauce.
Preheat the oven to 425F(220C), with the oven rack positioned in the center.
Toss 5 cups peeled butternut squash cut into 1-½-inch cubes on a rimmed 18 x 13-inch baking sheet (lined with parchment, if you like) with ½ cup sliced yellow onion, ¼ cup extra virgin olive oil, 1 teaspoon salt, ½ teaspoon crushed red pepper, and ½ teaspoon freshly ground black pepper. Arrange in one layer. Roast 15 minutes. Add 2 cloves finely chopped garlic and ¼ cup fresh sage leaves, and stir the squash around. Continue roasting 10-15 more minutes, or until the squash is tender and the onion is browned on the edges.
Scoop out 1 ½ cups of the roasted squash mixture from the sheet pan and set aside in a small bowl. Scrape the remaining squash, sage leaves and all the pan liquid into a food processor or blender. Add 2 cups vegetable broth, ¼ cup of the Parmesan and 2 tablespoons butter. Puree until the sauce is completely smooth, with a thick, pourable texture. Add additional broth as needed. Keep the sauce warm while the pasta cooks.
Bring 4-5 quarts of water to a boil in a large pot, then add 2 tablespoons kosher salt. Cook the pasta until al dente and drain. Transfer to a large serving bowl.
Add the sauce to the pasta, along with the reserved roasted squash. Serve hot, with additional Parmesan cheese.
Notes
Use precut squash from the produce department of your grocery store to cut down on prep time.
One medium-large (2-1/2-3 pounds) butternut squash should yield 5 cups of peeled, seeded cubes, to yield approximately 3 cups of sauce.
The sauce and roasted squash cubes can be made up to 5 days ahead and refrigerated. While the pasta is cooking, reheat the sauce and squash mixture in a saucepan on the stovetop over medium heat.
Frozen butternut squash works in a pinch — spread it on the baking sheet (not thawed) and add 10 minutes to the roasting time. It won't caramelize as deeply as fresh, but the sauce will still be creamy and flavorful.