The butterbeer at Universal Studio's Wizarding World of Harry Potter is delicious, don't get me wrong. However, it is a far cry from the original recipe to this brew that dates back over 400 years.
YouTuber How to Drink recently recreated the OG version of the foamy, buttery drink, which draws together its description from the Harry Potter series with the actual recipe. Found in The Good Huswifes Handmaide for the Kitchin, published in London in 1588, this "Buttered Beer" was almost more of an alcoholic custard than a beer, as How to Drink's recipe video shows.
The process of making it is similar to cooking custard, tempering it with a mulled ale, and then melting in hefty quantities of butter. The result is slightly alcoholic, as some of the beer's potency will evaporate during the process. However, it is warm, frothy, and quite sweet, just like J.K. Rowling describes it in her iconic novel series.
If you're looking to make a legitimate butterbeer recipe, this is likely the one to turn to. It'll also help keep everyone warm during the holidays and makes for an interesting alternative to eggnog for the grown-ups.