In a small saucepan, combine 1/2 cup sugar and 1 cup water.

Heat over medium, stirring until the sugar dissolves completely.

Remove from heat and let it cool to room temperature.

In a large pitcher, mix the cooled sugar syrup with the remaining 3 cups of cold water.

Stir in 1/2 cup freshly squeezed lemon juice.

Muddle 1/4 cup fresh mint leaves using a muddler or the back of a spoon to release their flavor.

Chill in the fridge or serve immediately over ice. Garnish with extra mint leaves or lemon slices if desired.