If using tea bags, steep two chai tea bags in 4 oz of hot water for 5 to 7 minutes. Remove bags and let the strong tea cool slightly.
In a tall glass, combine the cooled chai tea (or concentrate) and the vanilla syrup. Add the optional sweetener if you prefer a sweeter drink. Stir well.
Fill the glass completely with ice cubes.
Pour the milk over the ice and chai mixture.
Stir the drink gently until all ingredients are mixed and the drink is cold. Serve immediately.
Notes
For a stronger spice flavor, use a concentrate made with whole spices like cardamom and cinnamon sticks rather than powder.
If you do not have vanilla syrup, mix 1/2 teaspoon of pure vanilla extract with 1 tablespoon of simple syrup.
Oat milk provides the creamiest texture similar to whole milk in coffee shops.
To reduce dilution, use less ice or chill the chai concentrate before mixing.