For soup: Melt butter in large, heavy-bottomed pot over medium heat. Add onion first, then garlic, and sauté until tender. Add broth, all squash and herbs; bring to boil. Reduce heat, cover and simmer until squash is very tender, about 20 minutes. Puree soup using an immersion blender. Or if you don’t have an immersion blender, puree soup in blender in batches. Return soup to the pot. Stir in cream, and season with salt and pepper.
*Since acorn squash is a pain in the butt to cut, I suggest slicing the squash in half, removing the seeds, and roasting at 400 for about 30 minutes or until the squash is soft enough to scoop right out.
For croutons: Preheat broiler. Arrange bread on a baking sheet. Drizzle olive oil over each bread slice and broil until golden brown, about 1 minute. Turn over, drizzle with olive oil,cheese, and thyme. Broil until cheese melts, about 1 minute more.