In a large pitcher, combine the freshly squeezed lime juice with white rum. Add sugar if you like your drink sweet, but keep it under two tablespoons. Whisk the mixture well until the sugar dissolves. This step forms the base of your mojito, balancing sweetness with tang.
In a cocktail shaker, add mint leaves and lime slices. Lightly muddle them to release their oils and juice. Be gentle—too much muddling will make the mint taste bitter. Once done, divide this mixture into serving glasses, creating a refreshing layer at the bottom.
Fill the glasses with ice cubes. Crushed or cubed ice both work, but crushed cools faster. Pour the rum and lime mixture evenly over the ice. This not only chills the drink but also helps infuse the mint and lime flavors into the liquid.
Pour chilled club soda into each glass. The soda brings fizz and lightness to the cocktail, making it refreshing and festive. Be careful not to overfill—leave a little space at the top for garnishing.
Gently whisk or stir the drink to blend flavors without losing the carbonation. Garnish with a sprig of mint or a lime wheel for presentation. Serve immediately while the fizz is still strong, and enjoy your homemade mojito.