In 3-quart saucepan, melt butter over medium heat.
Add onion; cook, stirring occasionally, until crisp-tender.
Add all remaining ingredients except cream cheese.
Heat to boiling.
Reduce heat; cover and simmer 12 to 15 minutes or until squash is tender.
In blender or food processor, place one-third each of the soup mixture and cream cheese.
Cover; blend on high speed until smooth, scraping down sides of blender if needed.
Repeat twice with remaining soup mixture and cream cheese.
Return mixture to saucepan.
Heat over medium heat, stirring with whisk, until blended and hot (do not boil).
If thinner consistency is desired, add additional vegetable broth.