Process avocados and next 3 ingredients in a blender or food processor until smooth, stopping to scrape down sides.
Pour mixture into a large bowl; stir in half-and-half and next 3 ingredients until smooth. Place plastic wrap directly over soup; chill 1 hour. Garnish before serving, if desired.
*Off-dry white wines such as Gewürztraminer or Chenin Blanc may be substituted.