Make the simple syrup: Stir the sugar into the warm water until completely dissolved. This creates a smooth base and prevents graininess in the finished lemonade.
Combine the ingredients: Pour the syrup into a large pitcher and add the fresh lemon juice. Stir well to combine.
Add the cold water: Pour in the cold water and stir until everything is evenly mixed.
Taste and adjust: Taste the lemonade and add additional sugar or water if desired. The perfect balance will depend on the tartness of your lemons.
Chill: Refrigerate until thoroughly cold. Chilling helps the flavors blend together beautifully.
Prepare glasses: Fill serving glasses ice cubes.
Pour and garnish: Pour the lemonade over the ice and garnish with fresh lemon slices if desired.
Serve: Enjoy!