Frozen Butterbeer

Directions

1. In a small saucepan over medium, combine the brown sugar and water. Bring to a gentle boil and cook, stirring often, until the mixture reads 240 F on a candy thermometer.
2. Stir in the butter, salt, and 1/4 heavy cream. Set aside to cool to room temperature.
3. Once the mixture has cooled, stir in the rum extract.
4. In a medium bowl, combine 2 tablespoons of the brown sugar mixture and the remaining 1/2 cup of heavy cream. Use an electric mixer to beat until just thickened, but not completely whipped, about 2 to 3 minutes.
5. Mix the remaining brown sugar mixture, ice-cream, and 1 bottle of cream soda. To serve, divide between 4 tall glasses. Fill each glass nearly to the top with additional cream soda, then spoon the whipped topping over each.