1 cup butterscotch schnapps
7 cups cream soda (almost one 2 liter bottle)
Carefully mix together just before serving, adding the schnapps to the soda then stirring gently to mix well, or the fizz will dissipate too soon.
I was unable to find non-alcoholic butterscotch flavoring, and since it was mostly adults at my party, it was easier for me to use the schnapps.
For those wondering about the alcohol strength, the schnapps is only 15% alcohol by volume, so there is just enough to make a house-elf tipsy and to give it the warm, buttery aftertaste to the fizzy cream soda. Yum! :-9
(I did make a refill batch during the party using 1 cup schnapps to a whole 2 liter bottle of cream soda, which was ratio of 1 to 8, but people tasted the difference and complained, so fair warning!)
Update: Torani's website says they make a non-alcoholic butterscotch syrup for drinks, but I have been unable to find it in my local stores. I found English Toffee flavor, but butterbeer made with that lacks the warmth that the schnapps gives.
Recipes for alcoholic drinks are intended for use by adults over the legal age limit to buy &/or consume said alcohol. Any use by persons under the legal age limit is not the responsibility of The Leaky Cauldron.