Add bourbon, cider, lemon juice, syrup, bitters, and egg white (if using) to shaker.
Dry shake for 15 seconds.
Add ice and shake again until chilled.
Strain into rocks glass with fresh ice.
Garnish with cinnamon stick and apple slice.
Notes
Use fresh apple cider for best flavor. Garnish with cinnamon or apple for added aroma and presentation. Egg white adds smooth texture but can be skipped.