Muddle the peach in the shaker using a pestle.
Place all ingredients except sparkling wine in shaker.
Add ice cubes and shake vigorously.
Double filter using a strainer into a glass filled with ice cubes.
Top up with sparkling wine and stir with a spoon.
Push the rosemary sprig through the prosciutto-wrapped peach and garnish the cocktail. Using a match, light the end of the rosemary sprig.
