2 oz. light rum
1 oz. fresh lime juice
3/4 oz. grapefruit juice
1/2 oz. maraschino liqueur
1 tsp. sugar syrup*
1. Put all ingredients in a blender with 1 1/2 cups of crushed ice. Blend until frappéd.
2. Pour unstrained into a chilled cocktail glass. Serve with short straws.
* Sugar syrup: Heat equal parts white sugar and water until sugar dissolves, then cool and store in a bottle. Sugar syrup is sold at liquor stores and gourmet markets as "rock candy syrup" or "simple syrup."