3 red Thai bird or Fresno chile peppers, roughly chopped, plus halved chiles for garnish
1 cup white rum
1 cup mango nectar, chilled
1/4 cup yuzu juice, chilled
1/2 teaspoon grenadine
Seltzer, for serving
Combine the sugar, chopped chiles and 1/2 cup water in a small saucepan. Bring to a boil, reduce the heat to medium and cook, stirring occasionally, until the sugar is dissolved. Transfer to a small bowl and refrigerate until cold, at least 1 hour.
Combine the rum, mango nectar and yuzu juice in a pitcher. Strain the chile syrup into the pitcher; stir until incorporated. Divide among ice-filled glasses. Add a few drops of grenadine to each drink and top with a splash of seltzer. Garnish with a halved chile.