Add the water to a small saucepan and bring to a simmer. Remove from heat and add the tea bag; let steep 5-8 minutes. Discard the tea bag.
Fill a cocktail shaker with ice. Add the tea, lemon juice, and vanilla. Shake vigorously 15-20 seconds. Stir in the cider.
Strain into two double old fashioned glasses filled with ice. Garnish with lemon twists.
