Squeeze the lemons to extract fresh juice.
Combine the lemon juice and sugar in a mixing bowl.
Stir until the sugar dissolves completely.
Add cold water to the lemon-sugar mixture and stir well.
Taste and adjust sweetness by adding more sugar if needed.
Chill the lemonade in the refrigerator for at least 30 minutes.
Prepare serving glasses with ice cubes.
Pour the chilled lemonade into glasses over ice.
Garnish with mint leaves and lemon slices.
Serve immediately and enjoy your refreshing lemonade!