1 cup sliced almonds
¼ cup icing sugar
¼ cup amaretto or 1 teaspoon pure almond extract
2¼ cups water
Put the almonds and icing sugar in a food processor and process until very finely ground and starting to stick together, scraping down the sides a couple of times. This is the oil from the nuts being released. Add the amaretto and process again to make a thick paste. Pour in the water and blend until the mixture is frothy.
Pour the mixture into a shallow freezer-proof container and place in the freezer until just starting to set around the edges.
Stir the mixture with a fork, breaking up any large chunks and dragging the frozen ice from the sides into the centre. Repeat twice more periodically, until no large pieces of ice remain.
To serve: Spoon into chilled bowls or glasses and serve immediately.
If the granita freezes solid, just scratch the surface with a fork and you will soon have light-as-air granita.