Drain cherries, if necessary, saving liquid. Puree cherries in blender or food processor. Add enough water to cherry liquid to make 2 litre . Add vinegar, cornstarch and cinnamon. Cook, stirring constantly until slightly thickened. Remove from heat. Add cream. Chill. Season with salt and/or sugar or more vinegar to taste. Serve garnished with sour cream for soup. For dessert, use whipped cream slightly sweetened and dusted with cinnamon or nutmeg as a garnish.