Combine the coffee, sugar, coffee liqueur, and vanilla and stir until the sugar dissolves.
Pour the mixture in a flat pan. Place the pan in the freezer for an hour.
Mix the semi solid mass with a large fork to break up the crystals and place it back into the freezer.
Repeat the above process every 30 minutes, I had to do it for 2 times before i get nice consistency of the coffee crystals.
Spoon the granita into pre chilled glasses and top with a dollop of whipped cream. Serve immediately.