Can vichyssoise (cold potato soup) be prepared ahead, refrigerated and the cream added the next day?
Using this recipe as a baseline, I don't see any reason why it would not work.
Of course, the entire soup is chilled. There is no reason not to completely prepare it the night before, refrigerate, and then serve it the next day. You will want to allow it to warm up to almost room temperature for service, as the linked recipe indicates.
