In a small saucepan on medium heat, combine the coconut milk, sugar and vanilla extract. Stir until the sugar is completely dissolved. Remove from heat and stir in the espresso and espresso vodka, if using.
Chill the base for a minimum of 2 hours or until very cold, preferably overnight.
Prepare in an ice cream maker according to manufacturers instructions.
Notes
Espresso vodka will lower the freezing point, and keep the ice cream a bit softer, making it easier to scoop right out of the refrigerator. However, it can be omitted.