How to Make It
Make rosemary simple syrup: In a small saucepan, combine 2 cups sugar with 1 cup water and 2 large fresh rosemary sprigs. Cover and bring to a boil, then let steep off the heat 15 minutes, covered. Remove rosemary and chill syrup.
In a large jar or bowl, mix 6 cups well-chilled standard gin such as Tanqueray or Seagram’s, 1 1/2 cups freshly squeezed chilled lemon juice, and 3 3/4 cups chilled pomegranate juice with 1 1/2 cups rosemary simple syrup. Right before serving, add 6 cups chilled sparkling rosé.
Pour into a decanter or pitcher and tie rosemary sprig around the handle or neck.
Make ahead: Simple syrup or cocktail itself (without sparkling wine) up to 1 week, chilled; up to
3 months, frozen.