Pour the espresso into 2 ice cube trays and freeze until solid, 3 to 4 hours.
Combine the frozen espresso cubes, half-and-half, vodka, coffee liqueur, sugar and vanilla in a blender. Blend until smooth.
Pour the mixture into chilled glasses and top with whipped cream if using. Serve immediately.
If you prefer a sweeter drink, you can add more sugar to taste.