This heady brew is based on Chatham Artillery Punch, a famous libation from Savannah, Georgia.
Combine zests, sugar, and vanilla seeds. Muddle zests with a muddler or a wooden spoon to release the oils, and let sit 1 hour. Add juices, and stir to dissolve sugar; stir in brandy. Pour punch through a fine sieve into a bowl. Refrigerate at least 1 hour and up to overnight. Combine brandy mixture and Prosecco in a 4-quart punch bowl, and add ice ring. Serve immediately.
An ice ring will keep punch cold without diluting it. Pour water into a large ring mold or Bundt pan, and freeze. If desired, first place thin citrus wheels or fresh herb sprigs in mold, then add enough water to partially cover. Freeze; when frozen, add more water (or punch) to fill mold. Freeze. Just before serving, unmold, and float, decorative side up, in punch.
