Universal Orlando officials said yesterday that the one-millionth mug of Butterbeer was sold over the holidays inside The Wizarding World of Harry Potter attraction, which has been open only since June. The nonalcoholic drink, served cold or frozen, was inspired by the “Harry Potter” stories of J.K. Rowling. Rowling approved the secret recipe for the butterbeer now served at the park. The Wizarding World of Harry Potter, situated inside Universal’s Islands of Adventure, has a been a sensation, boosting park attendance 36% in its first three months.