Combine in shaker the gin, red wine, pomegranate juice, and rosemary orange simple syrup. Add ice and shake until chilled. Strain into chilled Collins glass, top with sparkling water and then add ice. Garnish with sprig of rosemary, pomegranate seeds and orange slice, if desired.
Rosemary Orange Syrup
Make simple syrup by boiling all ingredients together in a 1-quart heavy saucepan until reduced to about ¾ cup, about 15 minutes. Cool to room temperature. Syrup will keep in airtight container, refrigerated, for about to 2 weeks.