Pour spiced rum, lime juice, simple syrup, and egg white (or aquafaba) into a shaker.
Dry shake for 15 seconds to create foam.
Add ice and shake again until chilled.
Strain into a rocks glass over fresh ice.
Garnish with star anise or a cinnamon stick.
Notes
Adjust the sweetness by modifying the syrup amount. Aquafaba offers a vegan-friendly foam alternative. A toasted cinnamon stick adds a smoky aroma and flavor.