In each of 4 short glasses, place 8 mint leaves and 1 teaspoon powdered sugar. Muddle, crushing mint to release oils. Add 1/2 cup (generous) crushed ice to each glass, then 1/4 cup bourbon, and 1 tablespoon water. Stir to blend, adding more powdered sugar if desired. Top each glass with several small sprigs of fresh mint.
2 large fresh mint bunches
4 teaspoons (or more) powdered sugar
1 cup bourbon
4 tablespoons water