In a bowl, whisk together granulated sugar, egg yolks and half of the milk.
In a large saucepan, heat the remaining milk, brown sugar, corn syrup and cream until very hot.
Gradually whisk the milk mixture into the egg yolk mixture, then pour everything back into the saucepan and whisk over low heat until mixture thickens slightly and coats the back of a spoon.
Strain the mixture into a bowl. Whisk in the salt, cinnamon and vanilla.
Transfer the mixture to a heavy duty freezer bag and submerge in ice water for 30 minutes to quick cool. Put the bag in the refrigerator for 4 hours or overnight to chill.
Before churning, add 1 tablespoon of vodka to the bag with the cream mixture and swish it around.
Freeze in the ice cream maker following manufacturer's directions.