Ingredients
Pineapple Mint Puree:
3/4 cup sugar
1 cup (packed) fresh mint leaves
1/4 pineapple, peeled, cored, cut into 1" pieces (about 1.5 cups)
Assembly:
1/4 pineapple, peeled, cored, cut into 1" pieces (about 1.5 cups)
4 limes, each cut into 8 wedges, divided
1/2 cup packed fresh mint leaves
2 cups light rum
Club soda
Preparation
Puree: Bring sugar and 1 cup water to a boil in a small saucepan, stirring to dissolve sugar. Remove from heat, add mint, and let cool completely. Meanwhile, place pineapple in a blender and puree until smooth. Strain mint syrup through a fine-mesh sieve into pineapple puree and pulse to combine. Transfer to a jar, cover, and chill.
Assembly: For each cocktail, muddle 2 pieces of pineapple, 3 lime wedges, and 1 T mint leaves in a cocktail shaker until lightly crushed. Add 2 oz rum and 2 oz pineapple mint puree to cocktail shaker, fill with ice, cover, and shake until outside of shaker is frosty, about 30 seconds. Pour drink into a highball glass (do not strain) and top off with club soda. Garnish with a lime wedge and serve with a straw.
Do ahead: Pineapple-mint puree can be made 3 days ahead. Keep chilled.
