Start with a large, naked butternut squash. Scoop out the seeds and chop it up. Rumor has it that you buy pre-chopped squash, which some members of my family are rather excited about, I myself sort of enjoy hacking it up with a big knife, although maybe I shouldn't admit that.
Once your squash is ready, move onto the onions, just give them a rough chop, you are going to blend it anyways. Then saute them in 3 tablespoons of butter. This is important, DO NOT SKIMP ON THE BUTTER. When sauteing things I am normally a very lackadaisical person when it comes to the amount of oil or butter I use, but with this I really feel like you need the full 3 tablespoons, if not a smidge more. Also, the smell of onions cooking in butter is one of the best cooking smells ever and I would hate for you to deprive yourself of that by going easy on the butter. Anyways, let the onion get nice and soft but not brown, and add the thyme (I have never used fresh thyme in anything, I always just use dried) and salt.
Then you toss in the butternut squash and a spoonful of sugar and stir it all around, letting the squash get slickly covered with butter and melted sugar.
Then you pour in 5 cups of liquid, the recipe calls for water but I add 4 cups of chicken broth and 1 cup of water, you could do whatever you want, and simmer it until the squash is cooked through. At this point you may want to fry up the prosciutto, I have a tendency to forget about it and then try to convince someone else to do it for me.
Here is where you pretend that I didn't get distracted and took more pictures, like of when I blended the soup with my immersion blender (depending on your squash you may need to simmer the soup a bit or add some more water to get the right consistency) and when I served the soup and had it prettily topped with crispy bits of prosciutto and croutons. Of course, instead of doing any of that I was happily eating my soup and then remembered my blog, jumped up and ran for my camera. I have turned into a very forgetful photographer and for that I am sorry. The recipe is here, and remember, 4 cups broth instead of water and don't bother with the squash bowls unless you really want to.