Butterbeer a Huge Success at Harry Potter Wizarding Word Theme Park - "Unofficial" Recipe Leaked

Butterbeer is the most popular food item at the new at Universal Orlando, according to Wizarding World of Harry Potter Universal spokesman Tom Schroder, with visitors lining up to try it.  Schroder said that about half the visitors to The Wizarding World sample butterbeer.
Guests describe the drink as tasting "like cream soda. It was somewhat thick, and it was really sweet, and then it got salty as you swallowed it, like butterscotch."

Travers said if he were trying to make butterbeer at home, he'd "start with a good cream soda." The hard part, he said, would be the topping: "It tastes like a Werther's caramel candy but the foam had the consistency of a dairy or latte type of foam. It's pretty dense; it floats on top."

In the Harry Potter books, butterbeer appears to have an inebriating effect, but the Universal version is nonalcoholic.  Below you can find both an alcoholic and a non-alcoholic version of the recipe.  The non-alcoholic recipe is supposedly THE recipe for butterbeer that was leaked, although Universal will not confirm that.

BUTTERBEER RECIPE

Start to finish: 1 hour (10 minutes active)
Servings: 4

•1 cup light or dark brown sugar
•2 tablespoons water
•6 tablespoon butter
•1/2 teaspoon salt
•1/2 teaspoon cider vinegar
•3/4 cup heavy cream, divided
•1/2 teaspoon rum extract
•Four 12-ounce bottles cream soda

In a small saucepan over medium heat, 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.

Stir in the butter, salt, vinegar and 1/4 cup heavy cream. Set aside to cool to room temperature.

Once the mixture has cooled, stir in the rum extract.

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.

To serve, divide the brown sugar mixture between 4 tall glasses (about 1/4 cup for each glass). Add 1/4 cup of cream soda to each glass, then stir to combine. Fill each glass nearly to the top with additional cream soda, then spoon the whipped topping over each.