In a large pitcher, muddle 1 cup mint leaves. Add rum, grapefruit juice, club soda, simple syrup and lime juice. Stir to combine. Set aside.
2
In a food processor, add remaining ½ cup mint leaves and sugar. Pulse until mint is finely ground and mixture is well combined.
3
Pour sugar mixture onto a plate. Run a grapefruit or lime wedge around the rim of the glass and dip into sugar mixture. Turn glass to make sure rim is evenly coated. Repeat with remaining glasses.
4
Fill prepared glasses with ice. Pour grapefruit mojito mix evenly into glasses and garnish with grapefruit wedges.
