Line a mixing bowl with a sieve, and pour the sauce into it, pressing all around with the sides of a rubber spatula to extract as much flavor as possible from the orange rind. Discard the rind.
05Add the 1 cup of heavy cream, and stir. Let cool. Pour the mixture into the container of a hand-cranked or electric ice cream maker, and freeze according to the manufacturer's instructions.
06Meanwhile, to prepare the butterscotch sauce, put the 1 1/2 cups of sugar into a 12-inch nonstick skillet, and cook, stirring, until the sugar is melted and becomes a dark caramel in color. Add the corn syrup, stir to blend, and remove from the heat. Stir in the butter to blend. Stir in the 2/3 cup of cream and the bourbon. Spoon the sauce over the ice cream and serve.