01 - Bring 4 cups of water to a boil in a medium saucepan over high heat.
02 - Remove saucepan from heat and add dried hibiscus flowers. Allow to steep for 10 minutes to extract full flavor and vibrant color.
03 - Pour the mixture through a fine-mesh strainer into a heatproof pitcher, discarding the spent flowers.
04 - While tea remains warm, stir in granulated sugar and honey or agave syrup if using until completely dissolved.
05 - Allow tea to reach room temperature, then refrigerate for at least 1 hour until thoroughly chilled.
06 - Fill glasses with ice cubes and lime slices. Pour chilled hibiscus tea over ice and garnish with fresh mint leaves if desired.