How to Make It
Combine the vodka, lime juice, and simple syrup in a large pitcher or punch bowl. Cover and chill for at least 2 hours or overnight. Add the ginger beer just before serving. To serve, ladle into punch or lowball glasses filled with crushed ice.
To make the ginger-mint simple syrup:
Combine ¾ cup light brown sugar, ¾ cup water, ½ cup peeled and chopped fresh ginger, and 4 sprigs of fresh mint in a medium saucepan. Bring to a simmer and stir to dissolve sugar. Remove pan from heat and cool completely. Strain out the ginger and mint and refrigerate the syrup in a covered container for up to 2 weeks. Makes ¾ cup.