To start, add the granulated brown sugar into a pan along with the water. Then, heat it over medium-high heat and allow it to melt.
Once all of the sugar has been melted, you can add the butter. Whisk it in until it has been fully dissolved and incorporated into the sugar mixture. Next, you can whisk it in the heavy cream. Set the caramel aside to cool completely.
Moving on, you can add more heavy cream into into a separate bowl. Whisk in the butterscotch-flavored syrup. Then, beat the cream until it reaches stiff peaks.
To assemble your drink, first pour some of the liquid caramel sauce into your large glass jar. Then, carefully pour in the cream soda so that it doesn’t lose it’s fizziness. Finally, top the drink with your butterscotch whipped cream topping.