1. To prepare sorbet, combine first 4 ingredients in a heavy saucepan, stirring with a whisk. Gradually add 2 cups water, stirring with a whisk. Bring mixture to a boil, stirring well with a whisk. Cool to room temperature; cover and chill overnight.
2. Stir sorbet mixture with a whisk. Pour mixture into the freezer can of an ice-cream freezer; freeze according to manufacturer's instructions. Spoon sorbet into a freezer-safe container; cover and freeze 1 hour or until firm.
3. To prepare compote, combine 1/4 cup sugar and cherries; toss well. Let stand at room temperature 1 hour. Serve compote with sorbet.
Dutch process cocoa is richer, darker and less acidic than regular cocoa. Look for it in the grocery store alongside the regular cocoa.