1 ounce freshly squeezed lime juice
1 ounce freshly squeezed pink grapefruit juice
1 tablespoon superfine sugar
6 to 8 fresh mint leaves
2 ounces light rum
3 to 4 ounces chilled champagne (or club soda)
Quartered grapefruit slice for garnish
1. In the bottom of a highball glass (or mason jar!), muddle the mint leaves, sugar, and lime juice until the sugar is dissolved.
2. Add the rum and grapefruit juice.
3. Fill the glass with ice and top with champagne.
4. Garnish with grapefruit slice.