You cannot mix a cocktail where a restaurant patron can see it.

The Law Explained

Known infamously as the 'Zion Curtain' law, restaurants were historically required to build solid partitions to hide the creation of alcoholic beverages from diners. The logic was that seeing a bartender shake a martini might glamorize drinking and corrupt children. Although mostly repealed and modified in 2017, many strict alcohol preparation laws remain in place.