1/2 cup espresso beans, finely ground, or instant espresso
2-3/4 cups water
1 vanilla bean
3/4 cup sugar
Make espresso coffee with the ground beans or instant espresso and 2 cups water. Add the vanilla bean, and chill in the refrigerator.
Combine 3/4 cup water with the sugar in a straight-sided saucepan. Bring to a boil, remove from the heat, swirl to make sure the sugar is dissolved, and combine with the coffee. Chill the mixture in the refrigerator for a couple of hours.
Discard the vanilla bean, and freeze the espresso mixture in an ice cream machine, according to manufacturer's directions.