Place coffee and sugar in a saucepan and heat until sugar is completely dissolved. Do not boil liquid. Add cocoa and vanilla extract and mix thoroughly. Pour into a metal bowl and cool.

Freeze in an ice cream machine. Or pour hot mixture into a roasting pan or large metal bowl to cool and place in the freezer for 1-1/2 hours. When it has started to freeze, remove and beat with a whisk. Return to the freezer for another 1/2 hour.