In a blender, combine the quartered limes, granulated sugar, and 2 cups of cold water.

Blend on high speed until the limes are completely pulverized and the sugar has dissolved, about 1-2 minutes.

Strain the lime mixture through a fine-mesh sieve into a large pitcher to remove any pulp and seeds.

Add the remaining 4 cups of cold water to the pitcher and stir well to combine.

Serve the Brazilian limeade over ice cubes in individual glasses.

Garnish each glass with fresh mint leaves, if desired.

Stir before serving and enjoy!