Combine all ingredients in a small saucepan. Cook for about 10 minutes or until fully melted and flavor of rosemary comes through. Let the syrup cool for about 15 minutes, once cools, remove rosemary and use in cocktail. Keep refrigerated for up to a week after.
COCKTAIL
Add all ingredients together, stir. String ice and divide into 4 champagne glasses. Garnish with a sprig of fresh rosemary, a ¼ of blood orange and a ¼ of grapefruit.