My lifelong dream has come true. I'm going to the grocery store tonight to try this out!!
1/4 cup sweetened condensed milk
1/4 cup butterscotch topping
2 tablespoons whipped butter, room temperature
1 1/2 cups vanilla cream soda
Combine condensed milk, butterscotch topping, and butter in a glass heatproof measuring cup. Heat in microwave for 1 minute. Remove and stir until butter has melted and incorporated into mixture. Meanwhile heat cream soda in another heatproof measuring cup for 1 minute 30 seconds.
Divide butterscotch mixture between 2 (10 to 12-ounce) mugs. Fill mugs with heated cream soda and stir thoroughly. Serve garnished with an old-fashioned butterscotch candy stick.