Prep your ingredients: Wash the mint leaves and juice the limes.
Muddle (optional): Add mint leaves and sugar to your blender. Lightly muddle with a spoon to release the mint flavor. This step boosts flavor but can be skipped if blending thoroughly.
Blend: Add lime juice, rum, and ice to the blender. Blend until the mixture is smooth and slushy.
Serve: Pour the frozen mojito into chilled glasses. Top with a splash of soda water if desired.
Garnish: Add a lime slice and a fresh mint sprig to each glass. Serve immediately with a straw.