Step 1

In a cocktail shaker filled with ice, add the rum, grapefruit juice, lime juice, maraschino liqueur and Simple Syrup. Shake well to combine. Strain into a chilled cocktail glass and garnish with a lime slice.

Step 2

Combine the sugar and 1 cup water in a small saucepan and bring to a boil. Cook, stirring, until the sugar dissolves. Remove from the heat and let cool completely. Keep covered in the refrigerator for up to a month.