In a large stock pot bring cream, milk and half and half to a simmer. In a mixing bowl beat yolks to a frothy consistency adding granulated sugar and brown sugar, pureed persimmons and pinch of salt . Using a laddle whisk in hot milk and cream mixture into yolk and sugar mixture tempering egg mixture not to curdle and return to simmering pot of cream and milk mixture stirring continuously over medium heat until the entire mixture coats the back of the spoon just prior to boiling. Pour into a large bowl and refrigerate a few hours to chill or place in large bowl over an ice bath to lower the temperature prior to freezing. Follow your ice cream maker's directions for freezing.