In your cocktail shaker, combine the cooled black tea, tart cherry juice, and simple syrup. Add 3-4 ice cubes to the shaker.
Shake vigorously for 10-15 seconds until the outside of the shaker feels cold. This ensures proper mixing and slight dilution for balance.
Using your fine mesh strainer, double-strain the mixture over the ice-filled rocks glass to remove any tea particles or ice chips.
Add 3 dashes of Angostura bitters directly on top. Use a bar spoon to gently stir 2-3 times, creating a beautiful marbled effect.