• Heat the oven to 425°F line a baking sheet with parchment paper.
• Cut the squash in half lengthwise, and remove the seeds and stringy membrane.  Brush the surface of the squash and onions with 2 tablespoons of the oil and set on the lined sheet pan. 
• Drizzle the cut area of the garlic with 1 tablespoon of oil. Wrap it in foil and place it on the sheet pan. Transfer the pan to the oven.  Roast for 45 to 50 minutes or until the squash is tender when pierced with a knife. 
• Scoop the squash flesh into a blender. Add the roasted onion and lemon juice. Unwrap the garlic from the foil and pick out the garlic cloves. Add them to the blender with the cream and process until pureed. 
• Add the butter, Parmesan cheese, salt, and pepper. Continue processing until smooth.

To Use Immediately:

• Heat the amount needed in a saucepan over medium heat, adding reserved pasta water in 1/4 cup portions, thinning the sauce until it does not spit.  Serve with your favorite pasta.

To store Pasta Sauce: 

• Pour into Ball canning jars to 1-inch from the top.  Cover and refrigerate for 3-4 days. Or cover and place in the freezer for up to 3 months.