It seems easy enough really, take a butternut squash and cut it in half. Scoop out the seeds and then place it cut side down in a roasting pan with about 3/4 cup to 1 cup of water and roast at 350 for about 40-45 minutes. My thinking was that I would roast it and then puree it and add whatever else to it after that for flavoring. And while the squash is roasting, I threw in a few shallots to roast as well. Two medium sized shallots was perfect. I do these like I do garlic... cut off the top, place them in aluminum foil and drizzle with olive oil. Roast for 40 minutes or so, or until nice and soft. They will squeeze out of the skin just like garlic does.
You can check to make sure it's done by piercing it with a knife. If the knife goes in and comes out easily and cleanly, you're good to go. Let the squash cool a little before handling it again and once you are able to touch it without burning yourself, peel off the skin. Cut it into chunks and then chuck it in a blender with the roasted shallots. You can use sauteed onions if you don't have shallots.
Now... what to add? Well add the cooking liquid if there is any left, first. This is a sauce after all, you don't want it the consistency of baby food. If there isn't enough liquid left in the pan add a little more water or chicken broth to the sauce. I would say you want at least 3/4 cup of liquid added to the squash in the blender, total. From there I added salt, pepper and about 8 fresh sage leaves. I happen to really love the flavor of butternut and sage and I had sage on hand. But if you don't, you can use parsley. I also added about 2 Tablespoons of extra virgin olive oil just for kicks and half a cup of grated Parmesan cheese and then let the blender rip on puree until it was all blended and smooth.
After my linguine was done cooking, I strained it and then put the squash sauce in the pasta pan to heat back up a little and then added the pasta, cooking them together for about 5 minutes tops.
It turned out quite nicely. It had a creamy richness without adding any cream at all. In fact, aside from the added cheese, this is actually a pretty healthy recipe... no cream, no butter. I think the only thing I would do differently when making this again is add more sage. It kind of got lost in the sauce. This one butternut squash sauce recipe was enough for a pound of pasta. Top with extra chopped sage if you like and some grated Parmesan.
If you make it, let me know how you like it!