In a cocktail shaker, lightly muddle 1 sprig of rosemary with the Aperol 5 times. Do not over-muddle rosemary. Fill cocktail shaker with ice. Add bourbon and grapefruit soda. Shake well, then pour, strained, into highball glass.

Top with club soda and sparkling wine, garnish with grapefruit slice and 2nd rosemary sprig, and serve. (Add more grapefruit soda if you like it sweeter)