Gather your ingredients... no trip to Hogsmeade required. ;)
Start off with some butterscotch sauce.
Pour in the cream soda.
Don't forget that rum! (After all this recipe is for 21+ wizards).
Now add a scoop of vanilla ice cream and mix until combined.
After dividing the mixture between glasses, top generously with whipped cream and drizzle with butterscotch sauce.
Turns out you don't need a letter from Hogwarts to enjoy a boozy butterbeer!
This guide was inspired by http://waitingonmartha.com/boozy-butterbeer-recipe/