Make the chai syrup by bringing 1 cup of water to a boil. Remove from heat and then steep tea bags, covered, for 15 minutes. Remove bags and add maple syrup. Bring to a boil for 3-5 minutes, then remove from heat. Stir in vanilla and let cool.
In a cocktail shaker, combine bourbon, lemon juice, bitters and 2 oz syrup. Shake to combine, then strain into a glass.
Top with sparkling water and garnish with cinnamon and star anise.