*you could also add a bit of any of these to the soup itself, to taste, but I find I actually prefer adding it at the end as a garnish. It allows me to control the amount for each bowl I eat according to my mood, and there's just something so enjoyable about mixing it in only slightly, so that each bite tastes a little bit different.
You can also make this soup with any other kind of squash you like, but I particularly like butternut here for it's rich, smooth texture and sweetness. The only squash I really wouldn't recommend is acorn -- I actually tried that first just to mix things up, and found that acorn squash was too watery and bland to make a really great soup.
Tutorial for roasting garlic, here:
How To Roast Garlic