Stirring granita during the freezing process lets large, flaky ice crystals form.
In a blender, puree cherries, sugar, and lemon juice until sugar is dissolved and mixture is smooth. Pour into an 8-inch square baking dish. Freeze 6 hours, scraping with a fork every hour (mixture should be icy and fluffy).
To serve, pour 1 tablespoon liqueur into each of 12 small bowls or glasses. Top with 1/2 cup granita and a small dollop of whipped cream, if desired. Serve immediately.
This granita can be wrapped and frozen, up to 1 week; scrape again before serving.
