Remove the saucepan from the heat and add the dried butterfly pea flowers.

Cover and allow the flowers to steep until the liquid develops a rich deep-blue color.

Strain the tea through a fine mesh strainer into a heatproof bowl and discard the flowers.

Let the tea cool completely until no longer warm.

Squeeze fresh lemons and strain out any seeds.

Add the lemon juice and granulated sugar to a large pitcher.

Stir until the sugar begins dissolving into the citrus mixture.

Pour in the cold water and mix well.

Fill serving glasses generously with ice cubes.

Pour the lemonade mixture into each glass, filling about three-quarters full.

Slowly pour the cooled butterfly pea tea over the lemonade to create beautiful layers.

Watch the blue tea gradually shift into shades of purple where it meets the lemon juice.

Garnish each glass with lemon slices.

Stir before drinking for a fully blended flavor and color.