Often used in Thai and Vietnamese cooking, lemongrass offers an herby lemon flavor which pairs well with mint in this beverage. Adjust the sugar level to your preference.
- 1 (5-inch) stem lemongrass, cut into chunks
- 3–4 tablespoons sugar, to taste
- 20–26 fresh mint leaves, divided
- 2 teaspoons lime juice, divided
- ½ cup chilled club soda or seltzer, divided
- Mint sprigs for garnish, if desired
Place the chunks of lemongrass and 2 cups of water in a saucepan. Bring the water to a boil, then reduce the heat to a low simmer for 10 minutes. Remove the pan from the heat and let sit for 3–4 minutes to steep the lemongrass.
Use tongs to remove the lemongrass chunks and discard. Stir the sugar into the lemongrass infusion until dissolved. Cover and refrigerate overnight at this point, if desired.
To serve, place 10–12 mint leaves in a tall glass. Gently crush the mint with a wooden spoon. Fill the glass with ice. Add 1 teaspoon lime juice and ¼ cup club soda. Pour in ½ to ¾ cup of the lemongrass water and stir.
Garnish with a sprig of mint, if desired. Repeat with remaining ingredients.