Puree cherries, water and sugar to taste in a blender until smooth. Strain through a fine sieve, pressing on the solids to extract as much liquid as possible. (Discard solids.) Process in an ice cream maker according to the manufacturer's directions until firm and slushy. Transfer to an airtight container and freeze until ready to serve.Advertisement
Make Ahead Tip: Freeze in an airtight container for up to 1 week.
Tips: To pit fresh cherries, use a tool made for the job--a hand-held cherry pitter; it also works for olives! Or pry out the pit with the tip of a knife or vegetable peeler.
No ice cream maker? Pour the strained mixture into a 9-by-13-inch baking pan and place the pan on a level surface in your freezer. Freeze, stirring and scraping with a fork every 30 minutes, moving the frozen edges in toward the center and crushing any lumps, until firm and slushy, 2 1/2 to 3 hours.