01 - Roll lemons firmly on the countertop to soften, halve them, and extract juice to yield about 1/2 cup.
02 - Combine lemon juice with granulated sugar in a pitcher and stir until fully dissolved.
03 - Add cold water to the lemon and sugar mixture, then stir thoroughly. Adjust sweetness or tartness as preferred.
04 - Fill glasses with ice if desired, pour the lemon mixture over, and garnish with lemon slices or mint leaves.