For the Mexican Cinnamon-Vanilla Syrup:
Scrape the beans from the pod and set both aside. Crush the Mexican cinnamon with a mortar and pestle. In a pot, bring water to a boil and add vanilla beans and cinnamon. Reduce heat to medium-low and add superfine sugar, continuing to simmer for 15 minutes. Remove from heat, cool, and refrigerate for 24 hours. Strain mixture and refrigerate. (It should have a silky, viscous texture, similar to a raw egg white.)
To Assemble and Serve:
In a cocktail shaker, combine ¾ ounce Mexican Cinnamon-Vanilla Syrup, lemon juice, salt, and gin. Add 6 to 8 ice cubes (ideally Kold-Draft ). Shake for 20 to 25 seconds before straining into a chilled coupe glass. Garnish with lemon peel and freshly grated cinnamon.