If using butterfly pea flowers or a teabag: steep the tea for around 5 minutes in freshly boiled water. Remove tea solids when the steep time is over.If using butterfly pea tea powder (blue matcha): just combine the powder with water.
Sweeten if desired and add the vanilla extract.Let the tea cool down by adding the cold water or ice cubes.
If you are using powdered tea that doesn't require warm water, you can skip the step of letting the tea cool down.
Optionally, serve with cooked tapioca pearls (boba) or small pieces of grass jelly.
For a layered drink, fill the glass with ice cubes and pour the tea and milk separately. Depending on whether you want the blue layer on the bottom or top, you can choose to pour the tea or milk first. Both options look great.