In a small saucepan, combine 1 cup of sugar with 1 cup of water. Heat over medium heat, stirring continuously until the sugar fully dissolves, which should take about 3 to 5 minutes. Once dissolved, remove from heat and let the syrup cool to room temperature for about 15 minutes.

While the simple syrup cools, grab a large pitcher. Add 20 fresh mint leaves, then pour in 1 cup of freshly squeezed lemon juice and ¼ cup of freshly squeezed lime juice. Gently crush the mint leaves to release their oils.

Once the simple syrup has cooled, add it to the pitcher with the muddled mint and citrus juices. Stir thoroughly to combine.

Pour in 4 cups of sparkling water into the pitcher, stirring gently to maintain the bubbles.

Add 2 cups of ice cubes to the pitcher and mix in 1 teaspoon of green food coloring if desired. Stir gently one last time and serve.